Stupid teenagers walking into obvious danger, too much media hype on a film (it makes me have really high expectations for it) and when you get to the end of the film and you still don't know what the hell was going on.

I agree... also I'm sick of seeing dumb b*tches who know there's a killer in the house and they go in and then screem for 10 minutes as they are getting chased and Then act like their lives should be spared.

Too much humor. I dont like horror-comedys for some reason.