I used to think I was picky!
I won’t go see a movie if it appears to be a star cashing in on a previous hit by rehashing the same storyline (The Patriot seeming to be a rehash of Gibson’s success with Braveheart or just about anything by Jackie Chan).
Sequels. While a second movie is generally acceptable, if not as good as the first, three or more is pushing it. Let the idea go already. The exception being something like LOTR that has a reason to go more than two movies other than cashing in on what worked before.
Movies starring an ensemble of attractive teenagers (Scream) or adults trying to be teenagers (Old School).
Stupidity as humor (Dude, Where’s My Car?)
A movie that is overhyped. I don’t like to be made to feel that I have to go see a movie, even if I already wanted to see it (Spiderman, Daredevil). I usually end up being disappointed.
In general I’ll wait for movies to come out on video anyway and I find myself renting movies I’ve never heard of if the back of the box describes it appealingly or it stars an actor I like.