I'd say anything with too much of Russel Crowe. Jeepers Creepers 2 was quite boring and rubbish compared to the original. Be Cool was amazingly boring. Undefeatable with Cynthia Rothrock is a very very cheesy film; rubbish. It's not really old enough for that to be excuseable either.
One of the worst films I have ever seen is one Van Damme one in some random town in the desert that starts off pretty well if I remember but then the action is rationed out so measely and there is absolutely no story, acting or anything of interest going other than that. Some of the characters made me feel ill/depressed they were so boring and annoying. The action, if you wait for it, is rubbish as well,
The other terrible film was some random foriegn made for TV film with terrible special effects, the worst acting (all unknowns). It was another film that was so bad it made me feel unhappy. It was something to do with archeology and aliens.