I was a youngster when I saw the previews for Texas Chainsaw Massacre (1974) and they pretty much had me terrified to walk around the small town I lived in at the time during late night hours. Then I watched it... yep, did the trick for me.
Another film when I was a very young child was Alice_Sweet_Alice. I don't really recall it and the reason I mention it is I have been thinking of looking for it to see if it was actually scary or not. I was I think 4 years old when I had seen it. (I wasn't supposed to be up)
A few others would include:
- The Exorcist
- The Devil's Advocate (I was tripped out when I watched it, apologies for sayin' but true)
- Cannibal Holocaust
- Another film I'm still trying to find which I never learned the title of.... whatever.
- more that aren't coming to me just now.
... peace.