Users repwhoring; posting of questions on Q&A sites so they can answer themselves
Overabundance of joke replies in each thread
Heavy handed NSFW policy censoring everyday and artistic content due to ambiguous definition
of "appropriate".
A photo of a woman on a beach wearing a bikini in context with an article is not "half nude NSFW",
get a grip **
Long time forum members thinking they own the forum, ganging up on newer members
Aggressive moderation and drive by moderation with no explanation why posts were
deleted or edited; moderators taking sides in debates
Having to register using Facebook
"Real name" policy means naive or non-PC opinion could affect your future job prospects
Disqus
Why we're using Facebook less
Finding too much click bait in your news feed or too many unfunny photos/videos
Fed up with memes
Updates from friends who don't post often being hidden
Friends with too much time on their hands drowning your feed in trivial minutiae about their lives
Fed up with the clunky user interface, seriously - this UX is intentional ?
Mobile app(s) sucks
Don't want to install separate messaging app to write occasional two word replies
Tired of having to block notifications from games
You don't care what or where other people ate today