My first memory of watching a film, any film at all, was Pet Sematary (thanks, Dad....) It wasnt the evil kid, or the friendly ghost with the split open head, but a flashback from the female lead's past. She told the story of her sister Zelda, who had spinal meningitis and was kept in the back room of the house. That flashback was some of the scariest shit to date. I dont know if it was the combo of being at the young age where we start forming our real memories and how creepy it was, but re-watching that scene takes me back to that little toddler who hadn't seen a horror movie ever before. I have to have a light on in this room to even type about it, yeeesh. What scares the shit out of you?
This is the best clip i could find. Enjoy.