1) Torture porn or any horror story where there's nothing supernatural involved, just crazy people with broken grasps on reality. If they are motivated by fundamentalist religion, this goes doubly so. Werewolves and aliens can tear through countless bodies and I'll probably love it, but once you have severely emotionally disturbed regular people dong the killing, I'm done. It always just strikes me as too real.
2) Kind of at odds with most people here, it seems, dogs or kids who survive horror/disaster movies simply because they are cute.
3) Bad physics. Like that damn golden statue spewing liquid gold in Desolation of Smaug. Dragons, mysitical forces, etc, fine but damn it, liquid metals do not behave in that manner.
4) Stupid sex movie cliches to keep from being rated R. Look, I had a rather adventurous sex life in my single days. I've also been with my wife for almost 15 years. In the hundreds of times I've had sex, not once can I recall the girl putting on her underwear after sex, but before falling asleep for the night. Nor has anyone ever taken the sheet off the bed and wandered around the house/apartment in said sheet. As a general rule, people tend to not be particularly shy around someone they've been naked with for the last few hours. Every time that happens on film, it just instantly pulls me out of the film.
and finally
5) Any movie/book about kids narrated by one of the kids as an adult reflecting back on how wise and amazing and astounding that part of their life was. Most kids (including me) are kind of oblivious about the big picture by virtue of being kids. If the most amazing part of your life wasn't within the last five years of where ever you are in life, you're doing it wrong.