The Omen. Aaaaaaaaaaaaaaaaaaaaa! I watched this on Halloween in high school. (The original). I made my friend walk me into my house when she dropped me off to make sure I didn't have any demonic children waiting for me in the dark entry way. Then I let her fend for herself as she made her way to her car and back home. Horrifying.
Interview with a Vampire. This may not have made the list if it weren't for the scene with Kirstin Dunst and a pile of dolls (among other things). That alone did it for me. Too psychologically horrifying to recover from.
Ernest Scared Stupid. No, I'm not kidding. There's a scene where a little boy checks under his bed for monsters, and when he comes back up the monster is on his bed and gets him. It took away the safety of bed for me, and I didn't sleep for days. What once was a household favorite (Ernest Goes to Camp, Ernest Goes to Jail, etc...) was now a nightmarish punishment. Thanks a lot Ernest.
That's it, as far as I can remember. So, I don't recommend any of these movies, especially Ernest if you're under 10.