The Ring was a fabulous statement about safety within our culture. And a terrifying one as well. LOVED that movie. The boy scared the crap out of me when he revealed the reality of the girl to his mother.
And of course, breaking the third wall is a horrifying image and metaphor.
Videodrome did it well (though it's dated) but, IMNSHO, The Ring did it better. I need to see the original
Jaws is, now, extremely dated (with our photorealistic CGI), but for its time it was GREAT. It literally changed (for a while) how people behaved on the beach and in the ocean.
That's reality-affecting horror.
Alien. Again, by today's standards it might seem dated, but this movie was the PERFECT "haunted house" movie, with Giger and Lovecraft influences to boot.
The Exorcist.........again, a culture altering movie. Not only did it FREAK people out, but it created a short lived religious revival. Apparently movie horror can generate a faith in a specific god.
However............... the ONLY movie to give me nightmares as an adult was SE7EN.
I saw this as soon as it came out on video.
And I had true nightmares (all based on dream-logic based in the movie) for 6 nights.
Then I waited a few days............and rented it again.......
John Doe is far worse than Jason or Michael. He's worse than Freddy, Pinhead (well, maybe not worse than Pinhead)......he's the "
crazy religious guy" living next door*.
And the "next door reality" is what scares me in movies.
*Not a dig on Christianity. Im sure all of us, Christian, Atheist, polytheist or otherwise, have all met the "
crazy religious guy/gal"