A couple come to mind. In horror movies, the people that walk backwards, maybe away from a sound or image, or walk backward into a room or door without looking first. This NEVER happens in real life.

Also as black comedians are quick to point out, you white folk are crazy. When something looks very bad going down, white people do not run away, they go investigate it further.

And a big one on rom-com's where the male and female lead don't like each other, but you know by the end of the movie, they will be a couple. (see and lifetime channel movie)