1.) Magical reloading guns and guns with infinite bullets 2.) Gratuitous female nudity (male nudity however...) 3.) Continuity errors where I can tell that this shot was from a different take than that shot (Like levels of liquid in a glass keep changing, or hair has curl over forehead then gone then back, etc) 4.) Things that blow up for no reason 5.) Musicals that cast known actors who don't sing over no-names who do 6.) People who are supposed to be driving but don't look at the road 7.) Women going to bed/waking up/in a coma etc with full makeup 8.) Cell phone reception in places like freaking Antarctica but connection cuts out when the plot dictates in places that should have perfect connection 9.) Man meets woman. It is hate at first site, but you know they will be knocking boots by the end of the movie 10.) Historical or geographic fallacies.
I hate that. If nudity will somehow enhance the movie, go right ahead. But if you need naked chicks so that people will want to come see your movie, you should probably think about putting a little more work into your screenplay.... That drives me insane.