It's getting to be a bit of an annoying problem. I don't recall that while I was growing up I had all that many powerful nightmares. Maybe I did. It just seems that lately--in the last several months--I've had more, and they've been worse. I'm not sure why exactly...
But usually when I have a nightmare, the images are related somehow to some very powerful or frightening image I've seen recently. For example, several months ago I watched a movie I knew was a horror film... watched about an hour and a half and saw nothing particularly scary--only to see something that scared the bejeezees out of me. I shut the movie off right then and then had nightmares about that one thing for weeks! I can still see it clear as day, too, unfortunately.
Since then--after several varied and some recurring nightmares, I decided I should try to avoid when possible any kind of "horror" film, or scenes in any movie that I think might be disturbing. It's served me well. Just the other night though I left watching a movie with friends because I had read a review on the film which suggested it had a theme which I thought could give me nightmares--I'm starting to take it more seriously, you see.
But my roommate actually enjoys these kinds of films, and sometimes while I'm sitting on the couch doing something on the laptop, she'll be watching something like 'House on Haunted Hill' or 'Jeepers Creepers' and so on. I've gotten better about deliberately covering my eyes in parts and leaving the room.
I was talking to my dad not too long ago and he mentioned the same thing--having nightmares, and so he wouldn't watch any kind of horror film. I'm getting to be the same way now--staying away from it entirely because I know I will see it. Stuff like that which frightens me, I keep seeing it, the image just burned there in my mind. When I think about the movies people watch these days... I really wonder what is wrong with us that some people actually enjoy these things. I know for me at least, it's not healthy to watch that stuff... it just makes me think that make it's not good for anyone.