I quit because they are boring, content and people are boring. I'm 30 now and before I had a group of friends with similar interests: high school and college. I was meeting new people with also similar interests so they were posting what was interesting to me and vice versa.
It was fun to be on FB, IG and such. But now when I lost touch with 99% of people it got boring. Some of them post pics of their kids, some of their job and so on. I don't care, I can't relate to that. I don't even talk to 99% of the people, so it turned into stalking each other.
Also following celebrities is not interesting to me, they live in totally different dimension. I feel like my "online social life" is dead.