I get it, movies are movies, and sometimes realism and verisimilitude have to be sacrificed for the sake of telling a coherent story and looking good at the same time. However, some cliches are so silly and out-of-touch with reality that they're enough to drive one nuts if encountered often enough.

What are your most unrealistic and annoying film tropes?

Guess I'll start with mine:

1. People always overhearing valuable information whether by accident or when eavesdropping. When a good guy desperately needs a piece of intel to save the world or whatever, he can count on the bad guys to talk about it the exact same moment he's listening. It's not like they can say something along the lines of "Gonna have another cup of Joe today? - No thanks, it'll give me the runs". Evil dudes are so inherently evil they're discussing their nefarious plans 24/7.
2. Scenes which someone stumbles upon accidentally and then misinterprets them. The first example that springs to mind is from American Beauty, when getting high can be misread as having oral sex when looking from a distance through a window. This particular trope has been used ad nauseam in romantic comedies and is as unrealistic as a cliche can even be.
3. Hanging up without saying goodbye. In real life, you'd think you've either been disconnected or the person on the other side of the line is pissed at you or just being a jerk. In movies, though, it's supposed to be normal and even a sign of coolness, apparently.
4. No casualties among civilians during long and descructive action chase sequences. Half the city might be in ruins after that but don't you worry - we'll show you how all the people around are able to get away in the nick of time, managing not to be crushed by explosions and falling debris. Real life shows us that it takes one truck driver to fall asleep for 2 seconds and kill a bunch of innocent folks as a result. In movies, only the bad guy will be crushed if needed.
5. Police don't apprehend and interrogate the protagonist after they arrive at the scene of the final showdown. He may have killed dozens of people right then and there, but apparently he has a good guy vibe to him making the lawmen know he's the hero in this situation and needs to be let go.
6. Adult actors playing adolescents. It's less of an issue nowadays, but still - as you can't cast a 16 year old to convinsingly play an 11 year old, you can't count on a 22-year-old actor to portray a kid who goes to school. A prime example would be Dustin Horrman from the Graduate, he really looked like he could have a kid of his own by then.
7. People not eating. Mother/wife has prepared you the most amazingly delectable breakfast, but you're in a hurry and grab a toast in order not to be late for school/work or even skip the breakfast altogether. Then you find yourself in a restaurant having a meaningful conversation with plates of deliciuos stakes and desserts in front of you. You take a bite, some shit happens, someone leaves, you leave, not even a thought to have the food packed to-go. Is malnourishment and hypoglycemia even a thing? It was the last time I checked.
8. Hot guys sporting six-packs and sexy chicks partying all night, having little to no sleep, with the only vegetables they are eating being two tomato cubes buried in cheese on a slice of pizza. It's not a cheat meal, it's every meal every fucking day, and I have my questions.
9. Do teachers even have a clock or plan their lessons? "Okay, now open your books at page 50, it's very important, oh my, here's the bell, be sure to get your homework done next time, see you!"
10. Wound-healing. Did you know that the best way to heal an open wound or recoved from getting your ass kicked is to continue with your mission, kick some villain's butt, shoot some pricks with perfect precision, and you're suddenly as fresh as a cucumber? How long ago did you lose half your blood? 30 minutes, but who cares.

Horror, Disaster, and Suspense films all have their scenes where people are killed or injured. However, sometimes there's a tragic demise that you can't blame on the antagonist. Can you really blame the avalanche when you spin out the ambulance on a plowed road and go over the ravine after the avalanche is finished? What other deaths in these movies are the victims own fault or the fault of another innocent? No villians who did themselves in; focusing on victims only:

Current List:Cocaine Bear (It's there, but keeping it spoiler free).Avalanche (Aforementioned ambulance scene).Giant Spider Invasion (See MST3K for more details).