I couldn't watch Children of the Corn - the first one - I was in 6th grade, and my friend Jackie had come over to watch it. Well, mom & dad said "NO" but my sister (5 years older) and her friends could watch it. So Jackie & I spent half the night watching the movie from under my bedroom door (which faces the TV in the den). The rest of the night was spent huddled together in the bed with all the lights on waiting for a crazy child-of-the-corn to jump out at us. To this day I cannot pass a cornfield without getting weirded out (and not to mention that my house I live in now was built where the cornfields used to be
)
I also couldn't watch Red Dawn (where the Russians attacked us) or The Day After (the one about the bomb) -- after my parents realized that *everybody else* was watching it, they let me, but only with them in the room to filter out anything too violent.