The first one I remember making an impression on me was Jaws. My mum took me to see that when I was a little girl and I have been fearful of whats in the water ever since. Oh and nightmare on elm street the first time I saw it when younger. And someone mentioned that real "type" people are scarier than monsters and I would have to agree. When I was a young teenager I saw a movie I think it was called Pieces or something like that, that was the most horrible movie I have ever seen.