I deactivated my first account 8 years ago, but got back on to re-connect with my old pals and acquaintances from back in the day. For that reason, it was fantastic.
After another year, I realized that I can't actually say ANYTHING interesting on this platform without offending someone. There's a lot of variety in my crowd. I have the sense IRL to know that not everything is for everybody, but that doesn't matter much on Facebook unless you want to spend hours and hours hand-crafting subsets of your friends for different topics (I don't). And I have zero interest in posting selfies or status updates of what's going on in my life, so that made the platform exceedingly boring and a waste of time for me. It's a shame, because it does work really well for "connecting" with people (in the shallowest sense of the word).
The reason really was politics. I've never learned anything new from these posts, they tend to just be the more bombastic restatements of things that everyone already knows about. I think they're a form of social signaling or posturing (people want to establish themselves as the most for or against... whatever their in-group is for or agains).
There's a funny onion article I've always enjoyed, "I don't like the person you become when you're on the Jumbotron".
https://sports.theonion.com/i-dont-like-the-person-you-becom...
There are people I am friends with, but I wouldn't want to be around when they're drunk. I feel the same way about some people on social media. The problem is, they tend to be the ones who dominate the platform. And it's new, so we're not really aware of the dangers - but I actually do think it may have a lot in common with alcohol addiction.