Life imitating art - What common movie plot devices are mistakenly believed by most people?

If you have a gun trained on someone and they refuse to cooperate, simply pulling the hammer back will instantly make them compliant. (“Look, I can shoot you 0.02ms faster now!”)

You can kill someone easily by twisting their neck with your bare hands.

Conversely, knocking someone on the head will instantly render them unconscious. They will suffer no ill effects, and will conveniently remain unconscious until you splash water in their face / give 'em smelling salts / bop 'em on the head again.

The most common form of amnesia causes you to forget your name and other personal details of your life, but you can remember everything else. (This one can vary a bit according to needs of the plot.)

I have never seen this in a movie/TV, although I suppose it could have been shown somewhere. In the movie “The Verdict” starring Paul Newman as a lawyer, he asked a question that he didn’t know the answer to and a big deal was made about the fact that this was a huge mistake, and it was a significant plot point.

The link doesn’t work for me (NB: I’m behind China’s Great Firewall), but I’d dispute this one.
A couple times in my life when something shocking/surprising and painful has happened to me, my first reaction was to drop down, low enough to touch the ground. And at least once where I’ve been moving quickly and something painful happened, I lost my footing and stumbled over, even though the pain was not in my legs.
I can try to guess why I behaved like this, but the important thing is that in all these cases the painful thing was not being shot and I had no movie expectation of what I should do.

I’ve never leapt backwards and fell flat on my back, but I doubt many people who are shot do that either.

That defribrillators start hearts. They actually stop them.

Never shock a flatline.

Defibrillators briefly stop hearts in the hopes that when the brief shock wears off, the cardiac muscle will remember how to pump blood again, as opposed to flailing around at random, which is called fibrillation, which is what it was doing, which is why you used a defibrillator on it.

This application of percussive maintenance works often enough to be helpful because the heart actually knows how to beat in and of itself; cardiac muscle just does that, which is why heart transplants work: You don’t need to reconnect nerves to convince the donor heart to beat correctly in the recipient. It will beat just fine under the influence of hormones without any direct connection to the brain.

The biggest lie movies tell is probably the lie that CPR works most of the time. It works 20% of the time or less, and even when it works, it might not leave much in the way of usable brain.

Can you smash high-rise windows by hurling a sizeable piece of furniture through them? (Where, by “sizeable”, I’m thinking of something that one person alone might be able to do.)

A bullet shot through the fuselage of an aircraft will NOT cause explosive decompression. They did that on Mythbusters.

There was an incident here in Minneapolis several years back where a man had crashed through a 17th floor ceiling-to-floor window and (miraculously) survived.

Some readers of this message board, might also find Cracked.com fun. This subject has been articled there once or twice, satirically but factually. The site covers many subjects with humor and facts. So on any given day, it is hit or miss, what you might find interesting and or funny. The fact checking can be slack as well.

Or possibly — just as a hypothetical — some enemy knowing of his strange obsession could weaken the frame by night in order that a good follow-through would be guaranteed.

Predatory animals aren’t monsters that attack you on sight or relentlessly chase you over several miles of difficult terrain while risking its life or suffering injuries. Maybe if it was starving. But under normal conditions if you came face to face with a lion or tiger it would probably look at you funny and then go back to doing whatever it was before. Not that it’s a great idea to hang around, of course.

Quite a lot of movies and TV films set in UK courts will get lawyers in a tizzy. Frequently, they show judges using gavels, US-style, which our judges never do.

Not to mention the central professional in a drama series (e.g. in recent examples, coroners and forensic pathologists) taking up causes and cases and, in effect, becoming their own detectives, because someone comes and pleads with them personally - it makes for good drama, but would never happen in reality.

All “monsters” ( regardless of type: real animals, dinosaurs, aliens, undead) will pause their pursuit to bare their fangs and growl-drool.

That one’s starting to turn itself around I think - in modern cop series it’s usually the clueless new guy (or dumb civilians trying to help the police) who helpfully draws around the bodies.

Which IRL is of course called “tampering with a crime scene”.

Aliens look a lot like bipedal humans but with either reassuring or horrifying facial mods depending on whether they’re civilized (see Klingons, Wookies, etc.) or beastly (see Alien franchise, etc.).

We don’t know what they do look like, but it’s a good bet that a lot less than “all of them” will be bipedal and about 6 feet tall.

On that topic, I recently came across an amusing bit of trivia : people in rural India have noticed that tigers tend to back off when you’re looking at them. So people working in places where tiger are an actual danger have taken to wearing masks on the backs of their heads, which seems to be working so far.

I understand that the TVE (Spanish PBS) police procedural Los hombres de Paco (Paco’s Men, named after the Spanish name of SWAT: los hombres de Harrelson) was triggered in part by cops and judges remarking on the amount of people who expected to be Mirandized, get that phone call, or who even tried to claim the Fifth.

I’ve read articles mentioning blue meth, copied from Breaking Bad.

One common trope is the bad guy calling the detective to taunt him and the detective struggling to keep the caller on the line long enough to trace the call.

No, the call does not have to last 10 seconds, 30 seconds, or whatever amount of time is needed as a plot device in order to make the trace. And from what I understand from my LEO contacts they do not routinely get taunting calls from suspects.

That a driver has to look at a passenger while talking to her, and you can do so for many seconds without having a crash. And when being suspiciously followed, the driver has to turn his head to look directly out the back window, distrusting the mirror.

Nobody ever has to fumble in their pocket for their keys for their car, which is always miraculously parked just outside the door. (Even when cars had keys.)

In every movie, it rains, there is a funeral, somebody vomits, and somebody drives a Volvo.

Cactus Wrens and Common Loons can always be heard in the background anywhere in non-urban North America. And you can’t go out the door at night without hearing an owl, usually a species that does not occur in that locality.

At funerals everyone wears black. Everyone including children. They also drive black cars and if it is raining they carry black umbrellas.

Funerals are also an excellent place for the person who murdered the deceased to show up (also wearing black) in order to intimidate the spouse of the deceased.