Signs kept some sleep from me for at least a year. I first saw it when I was like 10 at night, so it creeped me out a lot. I always manage to scare myself whenever I hear noises in the night, thanks in no small part to that movie haunting me to this day. Although, I'm sure if I were to watch it now, it wouldn't scare me much.
Also, some old Goosebumps book scared me. I honestly can't remember a single detail about it at this time, but I remember it scaring me shitless at my grandparent's house...
I mostly avoid scary stuff now, because of those adverse reactions as a kid. My friend was laughing all through the new Friday the 13th (I think..?) but I know I would have been legitimately scared.