The Paradox of Horror

Last night, a few friends and I had a dinner party at Lindsey's house which ended with us watching a "scary movie", The Strangers. This movie got me thinking about the paradox of horror, and why we actually watch these scary movies. I, for one, do not watch scary movies all that often. I don't enjoy having to go home and try to fall asleep without thinking of ghosts, demons, or aliens attacking me at night.
The movie The Strangers does not involve supernatural villains, but villians who are other humans. The villians, for no apparent reason, attack a couple living in the middle of the woods. Watching this movie made me realize that I don't find horror movies scary unless the villians are supernatural, and this brings me to the paradox of horror.
I think that people watch horror movies for many different reasons, because everyone is different. It is hard to pin down one answer that will encompass everyone's behavior and motivation for enjoying the horror genre. My best guess, which involves my own personal motivation, is that people subject themselves to horror because we want to experience new situations. The situations in horror movies are sometimes things that could happen to us in real life and sometimes things that are unlikely to happen or that people have only claimed to have happened. Watching the horror movies helps us be prepared to experience new situations. We can run through what we would have done, had we been the character in the movie. While the six of us were watching The Strangers last night, we had a running commentary involving things like, "Why doesn't she just give up and let them kill her?" and "She should just shoot them, she was right there!" It's almost like playing a video game.
In psychology, we learn about people that we deem "sensation seekers". This type of person doesn't have very high arousal in the average state. They are always looking for new experiences that will increase their arousal. They're characterized by risk taking, spontaneity, and being outgoing. I would predict that another motivation for enjoying horror is that some people use it to increase their arousal! Those that are low in sensation seeking might still enjoy scary movies, but they may enjoy it for other reasons, such as practicing for a zombie invasion!