I guess I'm just immune then. I saw all three of those and didn't find them scary in the least. I enjoyed REC though, it was visually interesting.
There are certainly horror films that make me uncomfortable though. The saw films, while ridiculous and not scary in the least, sometimes make me unfomfortable. I don't understand why anyone would want to watch overtly realistic torture scenes that seem to serve no other purpose but to force you to watch someone getting mutilated.
It's hard to explain.
Nightmare, Friday and TCM all had overtly violent scenes in them, but the focus wasn't on the act and they weren't lingered upon. They way they did it, everything seemed downright comical. The early hellraiser films centered around torture, but again, it's all in the presentation. It seemed almost artistic in those films.
I still wish somebody could make a film that genuinely scares me though. I think I'm too familar with the genre... I see everything coming a mile away, even on the really good ones.