The movie that haunts you.

Lilya-4-Ever (2002)

I remember writing that the end of Jacob the Liar (1974) would haunt me forever. But that being the case I must have compartmentalized it, I never think about it, I try and not be haunted by anything.

I saw I Spit on Your Grave (1978) at a young age and it has always stuck with me.

Threads (1984) - it still gives me night terrors thinking about it.

The Entity(1982),so scary and i still can't watch it alone.

When I was a child someone let us watch A Nightmare on Elm Street and I still have nightmares!

On the Beach - the movie and book continue to be the most disturbing portrayal of the end of the wold. Everything seems so normal, when everyone knows it isn't.

Ghost Story (1981): https://moviechat.org/tt0082449/Ghost-Story
This one caught me off-guard due to its trite-sounding title and a misleading promo that aired when it was run on Showtime. It sounded like it was about a bunch of old guys sitting around telling scary stories, and I thought "meh," at least it's something to watch because I had nothing else to do at the time.

The plot was nothing at all like I had anticipated. The scene that haunts me involves the gruesome manner in which one of the characters dies.*

* The older guys have a secret they have kept for decades. Back in their younger days they believed they had accidentally killed a woman, and hastily figured they had better dispose of the body before someone discovers it. They decide to put her body in the back seat of a car and push the vehicle into a lake. It turns out the woman was only unconscious, and the cold lake water revived her as the car was sinking. She is shown pounding on the window trying to break out as the car fills up with water. The guys watch helplessly from the shore as she drowns. The combination of her slow suffocation and the men unable to stop what they had done just made me cringe; in fact it still does until this day.