the sheets - always L shaped, to cover the woman up to her shoulders but the man's chest can be seen
every phone number in America starts with or includes 555
nick a car and drive off? no problem, the person you took it from is your exact height which is why you don't need to adjust the seats or the mirrors
fish tanks - the bigger they are the more likely they will at some point be demolished in a spectacular fashion
blood stains - stays bright red even after months or years
bruises, broken bones and even gunshot wounds heal incredibly quickly
fingerprints taken off buttons are almost always perfectly intact
mobile phones - never need charging, nor do they run out of batteries, unless....
mobile phones run out of battery at the exact moment the hiding person's pursuers are just about to walk off.
darn it, who saw that coming?
drivers do not need to watch the road. looking at and talking to the person in front passanger seat will suffice, the longer they hold each others gaze the faster they can go!
bombs with timer counting back - they get diffused the very last second. count on it!
also the hero must close their eyes and make faces when cutting the wire as these gestures will ensure protection just in case the bomb explodes.
underwater scenes - apart from in Saving Private Ryan's opening scene jumping into water will ensure your safety acting as an invisible shield against a hail of bullets