The two movies that creeped me out the most growing up were HOMOCIDAL which I saw quite by accident on a double bill at the local bijou with something I actually wanted to see and STRAIGHT-JACKET with Joan Crawford that a friend dragged me to against my better judgement. Sordid, ugly, gratuitious little films that gave me nightmares weeks after.
I still haven't seen parts of THE FLY. I close my eyes. My wife announced last night she wanted to go see SAW. She did not appreciate my snort of disgust and pronouncement that I had no desire to see this crap. She'll go see it alone.
Once we got to the point of being too old to trick or treat, a group of my buddies and I used to congregate at a friend's house to hand out the treats. We all dressed up as various monsters, Dracula, Frankenstein's monster, Mad Scientist...one guy's dad worked for 3m, so he had access to a lot of free masking tape. He was the Mummy. I dressed as Igor the Hunchback. I always got to answer the door. That was as far as some kids ever got before they turned around. Scaring the little nose-picking buggers was fun!