Why do i enjoy horror movies yet they go against all human instinct?

Escape: It's an escape. You enjoy things that you won't (hopefully) ever experience.

You know best: There are all kinds of possibilities, and you have the best information about your own personal preferences. Some people enjoy the rush of being scared, but in a contained & controllable way. It can also be a way to re-experience an emotional state known from before -- not necessarily from the exact same stimuli. Or even a way to fight fear by withstanding scary circumstances. Look within & see.

Proximity: Because it brings you about as close as you can get to your biggest imagined fears but you're protected by the fact that it's only a movie. Freud posited that a fear is also a wish. We fear to images we see in movies but we simultaneously like to get as close as we can without being touched by it. Rubber necking a bad car accident is an example of how this manifests in real life.