I'm not in the "I'm leaving Facebook once and for all", actually I don't have that intention whatsoever, I am (was) a normal, active user. But it stopped being interesting. The kind of interaction Fb promotes is similar to twitter; in the first years I could see my friends showing off their breakfast or sharing their thoughts about something, now everything is 3rd-party articles, photos, videos, and complaining... LOTS of complaining (via sharing a relevant article they just read).
Ironically I still write to share my thoughts on something, without photos or shocking videos, and it catcyes my friend's attention because of the "novelty" of writing something of my own instead of just sharing some link.
Btw I've NEVER wanted to install Fb apps, especially since they forced everyone to have the Messenger app if you want to chat. Always used m.facebook.com for checking out, and mbasic. for chat (with the added benefit of the crappy UI pushing me out from using it...). Similarly, Twitter is another service I use, and never wanted their app installed, instead I use their website. The same reason frequent use of Reddit is out of the question for me.
People stopped making posts about their daily lives, removing the thing that attracted most of us to Facebook to begin with: The possibility of following the life of friends and family, even if we don't have the chance to see and talk to them in real life as often as we would like.
As post by real people have died out, ads, promotions and link spam have taken over and now fill our "news feed", making Facebook less interesting.
If Facebook didn't have private groups, users would be leaving much faster. Still, it's interesting that none of Facebooks strategies seems to revolve around getting people to post more original and personal content.
I quit Facebook last year, and maybe I would have stayed, if they had a feature that would allow me to hide everything not directly posted by friends. Then again, maybe not, it would have left me with very little content.