I've been trying to get into Mastodon about twice a year since 2017 and only now do I understand why it never sticks with me:
People here are Smart and Nice (and a little smug about how Smart and Nice it is)
Which is fine! Lovely, even! But it is not what I want.
I want Smart and Mean. Twitter was home for Smart Mean people. People who were mean enough to be funny but smart enough to choose good targets for that meanness.
Twitter let Smart Mean people be mean to Dumb Powerful people.