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Good and Bad Ideas

Title text: While it seemed like a fun prank at the time, I realize my prank fire extinguishers full of leaded gasoline were a mistake.

Explanation

This explanation may be incomplete or incorrect: Created by a BLOOD FOR THE BLOOD GOD- Please change this comment when editing this page. Do NOT delete this tag too soon.

This is a scatter plot comparing how good an idea sounds to how good the idea actually is. For example, leaded gasoline sounds like a good idea due to the anti-knocking effects, but is actually a bad idea due to lead toxicity. Fake prank fire extinguishers however sound bad and are bad as they can result in a dangerous situation in an emergency. Putting mold on infections sounds like a bad idea, but this could be referring to Penicillin, an antibiotic.

The title text combines leaded gasoline and a fake prank fire extinguisher into something that is worse than either. Not only is the fire extinguisher fake, it also releases flammable material onto the fire, and there is the additional lead toxicity.

Idea	What it means	How good it sounds	How good it actually is	Explanation
Leaded gasoline	Adding tetraethyl lead as an antiknocking agent to allow for increased performance	++	---	Leaded gasoline was introduced in the early 1920s to allow higher pressures and temperatures in an engine without causing detonation (knocking), allowing for increased fuel efficiency and engine performance; it also works to prevent engine valve wear. In essence, it artificially raises the octane rating of the fuel, reducing the need for refinement of the fuel, thus reducing waste and/or expense. Lead, however, is both toxic and bioaccumulative, meaning that lead released into the air over decades built up to harmful levels in people (as well as other animals) and almost certainly contributed to a host of health issues. Some scientists even suppose that crime level depends on lead exposure. (It should be noted that this only "[sounded] like a good idea" due to deliberate campaigns to obscure the known dangers).
Bloodletting	Releasing "bad blood" from the veins	---	---	You need (most of) your blood. Losing more than 15% of a person's total blood volume results in adverse effects. Bloodletting has been performed as a medical procedure for at least 2000 years until the 19th century. The idea was to withdraw blood to balance the body's "humors". Despite this long history, the notion that bleeding someone is bad seems like basic common sense, and it's now well-understood that blood-letting (outside of certain rare and specific cases) does no good, causes significant harm, and quite certainly caused many deaths when it was used.
Asbestos	Mineral which does not burn, tolerates extremely high temperatures, and forms small fibers. These qualities make it excellent for insulation and fire protection	+++	---	Asbestos was used extensively in ships and buildings throughout most of the 20th century. Unfortulately, the microscopic fibers which make up asbestos greatly increase the risk of cancer when inhaled, causing its use to be banned in most countries.
Extension cords with prongs on both ends	allows easy connection between 2 female connectors	0 (neutral)	---	Prongs on both ends would make it easier to plug the extension cord in on either side. But once plugged into an outlet, the other end becomes a serious shock hazard, as seen in this Backyard Scientist video.
Stair kayaking	Riding down a flight of stairs in a kayak	--	---	Stair kayaking is a stunt where a person positions a kayak at the top of a flight of stairs and then, using their paddle to push off, rides the kayak down the stairs (Example video showing kayaking down an escalator shown here). This poses significant easily foreseeable risks of injury or death, as well as being very bad for the kayak, which is designed to ride on water, not stairs.
Fake prank fire extinguishers		---	---	The idea of placing fake fire extinguishers as a prank, presumably so that a person who thinks they are grabbing a real fire extinguisher will instead find a decoy, sounds very dangerous and potentially life-threatening for many people, and it would, in fact, be highly dangerous. In the United States, (and presumably most countries), this would also be a felony in most, if not all, jurisdictions. An example of a similar situation, although not intended as a prank, can be found here. The title text expands this idea by having the prank fire extinguishers filled with (leaded) gasoline. This is literally adding fuel to the fire.
Always saying what you think	...regardless of the feelings of others or other considerations	++	--	Openness and honesty are seen as positive character traits in people. However, taken to the extreme of always telling people what you think about them, they can lead to awkward or unpleasant situations. It may harm your relationship with the other person if they don't like what you think, or they may reply without concern for your feelings or other considerations. Keeping negative thoughts to yourself or telling "white lies" can be considered a better alternative in some situations.
Replying to spammers	Clicking on the "Reply" button from spam mails and writing (and sending) a reply (or worse, clicking on the links in these mails)	--	--	At best, you confirm your email address and identify yourself as someone likely to respond to such unsolicited messages, and so encourage the spammers to deluge you with even more messages. At worst, the spammer may use your correspondence to extract sensitive information about you, or make you victim to a scam.
Solar cars	Having solar panels on the car's surface (mostly hood and roof) for power generation	+++	-	Powering electric vehicles with solar panels seems like an excellent idea: it would provide free power with no increased land use, and theoretically could allow a vehicle to operate indefinitely without being fueled or charged. However, such vehicles couldn't operate without batteries (due to power requirements, weather and shade conditions, and nighttime driving), so they'd have increased complexity compared to plug-in or hybrid cars. Adding solar panels would add cost, weight, manufacturing complexity, and maintenance requirements. Solar panels on moving cars are less efficient than in stationary installations, and subject to damage from both collisions and road debris. Solar cars do exist (the World Solar Challenge is a competition for such cars), but as a practical form of transportation, the negatives likely outweigh the positives.
Heelies	Heelys are shoes with a inline skate wheel embedded in the sole, at the heel.	+	-	Heelys allow the wearer (usually children) to shift between normal walking and rolling like a roller skate. This sounds like fun but has led to numerous injuries.
Prequels	A work of fiction (mostly movie) telling the "story before the story" of another work of fiction.	+++	-	More of a good story sounds great on the surface, and audiences who are invested in a set of characters and/or a setting often love the idea of finding out what led up to certain events. But there are a number of pitfalls. Any spin-off of a popular property risks becoming a low-quality cash grab. Prequels, specifically, are constrained by the fact that they have to lead to the story that's already been released, which can lead to contrived storytelling. There's less room for suspense, since the future of the storyline has already been established. There's a tendency to invent or fill in detailed backstories, which can undermine character arcs, and/or destroy the mystery and nuance of certain characters. It's not impossible for prequels to be good, of course, but there are a lot of ways they can go wrong.
Transitions® lenses	A brand name for photochromic lenses in glasses, which get darker (like sunglasses) in bright light.	+	-	Photochromic lenses are clear lenses that darken when exposed to UV light, then turn clear again when the exposure is removed. The advantage is that wearers of glasses don't need to buy separate (prescription) sunglasses. However, the process is relatively slow (about a minute) so not so useful when there is a quick succession of shade and bright light, perhaps in a forest or when driving. Also, car windscreen filter out UV light to some degree, which prevents the glasses from darkening as required. Finally, the process is temperature dependent, so in hot weather the glasses don't become as dark and in cold weather they might stay dark for too long.
Cutting pizza in squares	Cutting (a presumably round) pizza in squares	-	-	Most people cut pizza into wedges and hold it by the crust. Cutting it into squares allows for more pieces to be shared, but pieces near the center will have no crust to hold it by, getting cheese and sauce all over your fingers. There will also be lots of leftover tiny pieces. While hardly a disaster like the other items in its quadrant, square pizza pieces are just not very useful and rather inefficient. Cutting a rectangular pizza into squares might not suffer from the problems above, but, unless the pizza itself is square and cut only into four squares, some people will end up with a higher crust-to-topping ratio than others. Cutting a round pizza into squares is popular in Chicago and is sometimes called tavern-style or party-cut and some[who?] consider it the real Chicago style pizza rather than deep dish pizza[dubious].
Project Orion	Study by the U.S. government looking into nuclear pulse propulsion for spacecraft.	---	-	Using repeated nuclear explosions to generate motion sounds bad for both the spacecraft and everything else, especially with a ground launch, but there are ways to address a lot of the concerns, so it isn't as bad as it sounds. Project Orion's theorized specific impulse and thrust would also be far higher than anything chemical rockets can accomplish. The efficiency of Project Orion is extremely low, however. See also comic 2423: Project Orion.
Soup	Soup	0 (neutral)	0 (neutral)	Soup is probably one of the oldest foods created by prehistoric cooks. Many people enjoy it, though some consider many soups somewhat lacking as a meal on their own, or boring.
Combo washer dryers	A device which combines washing machine and laundry dryer into one device	+++	+	Better at space efficiency, but worse at each task than separate devices.
Cutting sandwiches diagonally	Cutting sandwiches diagonally	+	+	Generally regarded as the superior way to slice a sandwich, providing more aesthetically pleasing display of the contents, better support in the hand and fewer all-crust bites. Required in the assembly of a club sandwich,[actual citation needed] where the diagonal components are stacked again.
Diverging diamond interchanges	Road junction where the two (sets of) lanes cross over to switch sides (so if you normally drive on the right, now you drive on the left), then switch back to normal after the junction	-	+	Highway engineers believe the shape improves safety and traffic flow through the interchange because switching to the other side facilitates merging to and from the other road in the junction. However the shape appears to be insanity to an unfamiliar driver.
Toasting sandwiches	Making a sandwich first and then cooking it, as in a dedicated sandwich toaster, a toaster oven or frying pan, or under a grill.	++	++	The grilled cheese sandwich is a familiar form to most people, and many other sandwiches are improved by toasting as a final step. Others, such as the Western or club are prepared using toast. The Elvis is a specific case of a sandwich that normally wouldn't be toasted, but is improved by it - peanut butter, bacon, banana, and jelly, with the assembly lightly fried.
Crumple zones	Designated areas of a car that crumple in case of a crash.	--	++	Most peoples' intuition would be that stronger cars are safer, and intending parts of a vehicle to collapse by design might seem crazy. But engineered crumple zones are designed to absorb the kinetic energy in a vehicle collision, and do so in such a way as to protect the passenger cabin. This significantly reduces the danger of injury or death from crashes.
Sliced bread	Bread, sliced by the baker before packaging for sale	+++	++	It's far more convenient for making sandwiches or toast, but unfortunately pre-sliced bread will go stale faster and some applications may be better off thicker or thinner than the slices provided. Sliced bread is often used as a comparator for how good something is in the phrase 'the best thing since sliced bread'.
Pizza	Pizza	++	++	Pizza is a widely popular dish throughout much of the world, uncontroversial except certain toppings.
Eating citrus fruit while at sea	Having a supply of citrus fruit on long sea journeys, especially during the Age of Sail	0 (neutral)	+++	For a long time, scurvy was a serious danger to sailors, who generally subsisted on a monotonous diet with low vitamin content while on ships. Most citrus fruits are rich in vitamin C, which prevents scurvy. Eating orange or lemons doesn't seem like a significant activity one way or the other, but it's an easy way to prevent a disease that causes serious ill-health and possibly a painful death.
Putting mold on infections	Seemingly a reference to ancient practice of pressing moldy bread against infected wounds	---	++	While this sounds like a good way to get a fungal infection, with the correct mold this is a primitive antibiotic, and led to the discovery of penicillin.
Wheels on luggage	Some luggage bags have small wheels inset on their frame and a carrying handle.	+++	+++	A relatively simple fitting for rigid or semi-rigid luggage that substantially eases its transport over long distances on flat surfaces such as travel terminals.
Heat pumps	Refrigeration (or air conditioning) technology operated in reverse to heat an area instead.	++	+++	Because refrigeration is a very efficient way to move heat (as long as the cold side's temperature is high enough) this is often far more energetically efficient than directly heating a space. Reversible heat pumps also exist which can take care of both temperature needs in some climates.
Laser eye surgery	Surgical techniques using lasers for precision cutting in the eyeball.	-	+++	In the popular imagination, lasers are often thought of as something used for destroying their target. Firing them into people's eyes, then, does not sound a great idea. However. this technology has substantially improved the eyesight of millions of people worldwide by allowing treatment of eye problems otherwise only corrected by lenses, or entirely untreatable. Randall has previously commented on laser eye surgery, amongst other ideas both good and bad, in 1681: Laser Products.
Fecal transplants	Transfer of gut microbiome of healthy person to sterilised gut of ill person.	---	+++	The gut microbiome is a collection of bacteria that lives in our guts. It can influence our health. It is responsible for last stages of digesting our food. It can also produce neurotransmitters that are carried by blood to our brain influencing our behaviour. A healthy microbiome can be destroyed by bad eating habits, unhealthy lifestyle, infections or antibiotics. The important part is a composition of different species of bacteria that compromise the biome. Sometimes it may be necessary to completely sterilise the gut and then take a sample of a healthy biome from another person. A sample is enough as the bacteria will multiply. As long as the patient eats correctly, the microbiome after transplant should develop correctly. It sounds bad because we tend to think of our feces as something gross, to be discarded. It is called fecal transplant as our feces contain about 50% of gut bacteria, but nowadays the sample usually takes the form of a coated pill that is applied rectally.

Trivia

A much leaner version of this comic appeared in the first "What If?" book, chapter "Weird (and Worrying) Questions from the What If? Inbox, #9".

Transcript

This transcript is incomplete. Please help editing it! Thanks.

[A graph of X Y axes with arrows at both ends.]

[X axis from left to right:]

Sounds like a good idea

Sounds like a bad idea

[Y axis from top to bottom:]

Actually a bad idea

Actually a good idea

[Top left quadrant (sounds like a good idea, actually a bad idea):]

Leaded gasoline

Asbestos

Always saying what you think

Solar cars

Heelies

Prequels

Transitions® lenses

[Top middle (actually a bad idea):]

Extension cords with prongs on both ends

[Top right quadrant (sounds like a bad idea, actually a bad idea):]

Bloodletting

Fake prank fire extinguishers

Stair kayaking

Replying to spammers

Cutting pizza in squares

Project Orion

[Center (neutral):]

Soup

[Bottom left quadrant (sounds like a good idea, actually a good idea):]

Combo washer dryers

Cutting sandwiches diagonally

Toasting sandwiches

Sliced bread

Pizza

Wheels on luggage

Heat pumps

[Bottom middle (actually a good idea):]

Eating citrus fruit while at sea

[Bottom right quadrant (sounds like a bad idea, actually a good idea):]

Diverging diamond interchanges

Crumple zones

Putting mold on infections

Laser eye surgery

Fecal transplants

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