Movies that frightened me:
Seven
Copycat
Jaws
Zodiac
Halloween
Magic
The Shining
I never saw The Exorcist because my friend boys who saw it first -- came back to their dorm, all slept in the same room that night -- one clutching a Bible to his chest. After that -- I was too afraid to go see it. LOL So that is probably one that would have scared me also.