I'm not a fan of horror movies. There's only a few times when I wanted to watch a scary movie with my family or friends. Some people can even watch scary movies alone. :/
I don't like scary movies that look fake ie ghosts and things that are made up by our imagination. Movies that are likely to happen in real life are the scarriest to me. So to me, the scariest horror movie would be The Texas Chainsaw Massacre. I've only seen this once but I vowed never to watch it again. I don't remember all the details of it but I remember how it made me feel: VERY SCARED!