Overuse of cgi and jumpscares ruin horror. So many movies think having a
LOUD NOISE is scary but being startled by a
LOUD NOISE isn't the same as being scared or creeped out. A
LOUD NOISE is not the same as being scared and I've seen so many horror films that the
LOUD NOISES just make me go
now. It's a cheap way to get a reaction out of the audience. But that reaction isn't fear or terror, it's being startled. Because of course something loud will startle you.
Good writing, characters, practical effects, atmosphere >>>>> overuse of cgi and jumpscares.
Jumpscares don't have a lasting effect. It happens and you're like "Wow that was loud" and it's over. Good writing, creepy atmosphere, mystery, etc can have you thinking about what you saw (or didn't see) long after the movie is actually over. That type of stuff stays in your mind because you remember how creeped out you got or the idea of a concept having so many horrifying possibilities.
Note: Some jumpscares can be effective but you need the build up to actually make the payoff worthwhile. Think of the build up as a joke and jumpscare as the punchline. David Lynch does this well. Here's a scene from Muholland Drive.
He knows how to do the dream like atmosphere and creepy/uneasy feeling well in general. Watch the scene above and see how slowly the fear sets in, the stiff like dialogue, the way the atmosphere doesn't feel right, the background sounds, this is all the build up. One of the best things is the fact that it all happens in broad daylight. A lot of horrors think the scene has to be super dark to be scary but that's not true.
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than the movie. Like many have said horror these days is just cheap CGI and jumps. 
just from simple story telling
