Ok, I will date myself
The Fly 1958
House On Haunted Hill 1959
House of Usher 1960
Psycho 1960
Pit and the Pendulum 1961
Premature Burial 1962
The Day of the Triffids 1962
Whatever Happened To Baby Jane 1962
Those are the movies that bothered me the most as a kid. I was between six and ten years old at the time. I think that's likely the most impressionable age and I was certainly taken in and completely bothered/entertained by them. There have been some great movies in the horror genre since I was little. None that effected me quite like the ones when I was a kid.