I am a recent convert to horror movies. Until about a year ago, they held no interest for me. I had a couple of bad experiences as a teenager and those events helped me decide that the genre was useless to me. Then I met my best friend.
I can't remember the first horror movie she talked me into seeing, but we had such a good time trying to scare each other during and after the movie that I decided to give the genre another chance. While I still don't care for slasher movies, the supernatural ones get my blood pumping and my adrenaline going. I think the key to not letting myself get freaked out is to remember that while the film may claim to be a true story or may seem realistic, it's only a movie. Even the "true story" films have to add drama to make it exciting, and many directors take great liberties with the real events.
I remember watching The Blair Witch Project in the theater in 1999. As I had been lost in the woods in the dark before, the movie terrified me. Years later, when I was teaching at a community college, I showed the movie to my class on Halloween. Several students fell asleep and the ones who stayed awake through the whole thing were wholly not scared.
Sure, what scares each person is going to be different, and the hand-held filming of The Blair Witch Project can't hold much of a candle to the special effects-heavy flicks that are being made today. But why was I (still) so scared of Blair Witch? Why do I go pay good money to see scary movies? Why does anyone?
The following list is compromised of horror movies that I have seen in the last year or so. Each movie is given a personal Scare Factor score (1 through 5) and is followed up with theories and research about why folks may find this film attractive. I do not get in to how/if horror movies influence real-life sinister behavior, but there is tons of research out there about it that's not hard to find.