As a young guy who unfortunately didn't grow up in the golden age of horror films (1970s-1980s), I honestly hate the vast majority of today's "horror" films. My reasons for it are because almost all of them just outright lack originality (I can understand that originality is almost impossible these days in entertainment but at least put some effort to throw in a few new ideas in the mix with the unoriginal things), they rely way too much on blood, gore and jump scares. They also rely way too much on CGI effects. I'm not trying to be a hipster or anything but that's really the truth about most of the modern day horror films
The only one modern day horror movie that came super close to scarying me the same way old classic horror movies like The Amityville Horror (1979), The Shining (1980) and Suspiria (1977) did is Insidious (2011) and that's because unlike most of today's horror films, while Insidious did utilize some jump scares, they didn't greatly overuse it and actually build up a terrifying feeling in you with many of their scenes.
I don't know man, I think Horror movies age really badly. The only classics I think stood the test of time rather well are the Thing and Alien. I would say the newer movies such as Pan's Labyrinth, The Babadook or Drag me to Hell have a more stable foundation going forward.
I think one issue with horror movies is that the better the movie is the less scary it becomes, which in turns means a lot of the good old scary "classics" weren't particularly great movies. Also, I don't want to question your taste but the Amityville Horror was... kind of really shit.
I don't really hate them but I do heavily dislike modern horror movies also. To me they are just too predictable, I know when there is going to be a jump scare because they make it so obvious. I also don't like that nowadays there are a lot more horror movies out there that mainly use the same formula but I did like a few of them but overall I find most of them the same and predictable.