shining exorcist psycho halloween nightmare on Elm street....the scariest film of all time I don't know
I find horror moves subjective.
To me, religious based films like the Exorcist are more in the fantasy genre becuase I don't believe in angels or demons and God/Devil do not do those sorts of things. I find possession haunting and ghost movies amusing rather than scary.
For a film to be a 'greatest' it must stand the test of time. The Shining, Psycho and the first Halloween do stand the test of time because they deal with the depravity of man's psycological stability. Something in real life which is as common today as it was when the films were made.
Nightmare on Elm Street is also pure fantasy to me. While people do still have nightmares, they cannot do what is depicted in the film. Its merely another amusing movie.
About films in general...
When watching a movie the 'goal' is to suspend disbelief and be 'pulled' into the movie.
In horror, one must be able to identify with the people in the film so it feels like its actually happening. It must raise the viewer's empathy to the point they feel the same terror as the characters in the film.
This identification with the film hinges on the acting ability, set design, story and the 'atmosphere' of the set.
Points are taken whenever you say "Wait, that doesn't make sense to reality or Wait, that can't happen in real life or Wait, nobody is that stupid."
Then you have the films that lead off with "Based on a true story" or "Based on actual events" and the so-called "Found Footage/Lost Footage" films are merely a cop-out to actual filmmaking.
To me, the best horror films deal with human depravity.
Split w/James McAvoy dealt with multiple personalities and was good horror.
It started to go fantasy towards the end and when
Glass came out it kinda ruined the personification but
Split on its own was good and does stand the test of time. Good movie, however, not really the scariest horror film.
Unsane w/Clair Foy deals with insurance fraud and society's definition of sanity. There were some over-the-top characters but the subject matter is relevent to common society expectations. Good movie but still, not really the scariest horror film either.
The scariest horror film ever are the NEWS broadcasts which are real life.
The coverage of war, the coverage of the 9/11 attacks as they happened and similar films. These horror films are real and proof of man's depravity.
Movies which realistically depict real-world threats are scary. Some are well-done while others add fantasy elements to soften the blow.
Home invasion movies, movies about serial rapists and murderers and movies which deal with mass shooting and lone snipers. Some episodes in Law & Order and Criminal Minds deal with horror. I, however, do not find any movie...scary.
Fear is subjective. I no longer have much fear in me because I am not afraid to die. I live in reality so my imagination stays separate from reality.
Some well-timed 'jump scares' will cause me a jolt but not that often.
I prefer creatures and monsters. Totally in fantasy but I like looking at the different designs and mannerisms. I also like movies which feature alien creatures. Who knows what horrors exist in the Universe?
I suspect if there were a list of the top 5 scariest movies they would consist of Lifetime type films like
The Burning Bed w/Farrah Fawcett.
The Movie of the Week films which deal with common human depravity. Subject matter which anyone might encounter during their own lives. This is because evil is not a force, its a mindset. Good and evil are subject to the individual and exist within.