30 reasons to quit Twitter:
1. Misinformation. Twitter is the new Truth Social and Musk is the new Trump.
2. No moderation. Post anything you want, there are no rules. Hate speech and crime is OK. There is hardly any moderation team left. It was bad before, but when Musk rose to power Twitter got rid of teams devoted to human rights and machine learning ethics. Twitter allows racism, homophobia, misogyny, misandry, xenophobia and terrorists and is not doing anything to stop it. It was bad before, but with Musk and no moderation team it's as bad as it can get.
3. No freedom of press. Most of the press have been banned. There is no press team in the Twitter either. And this social media should be the one to be cited in news, come on. Twitter is no longer a friendly place for a journalist.
4. No freedom of speech. Remember when Musk banned everyone who made fun of him and everyone who mention other social medias or Mastodon? The banning still continues if he disagrees, it's just not that visible any more.
5. Hate speech and toxic behaviour. See 2. It's not fun to be bashed after every post.
6. Obscenity and trolls, Musk being biggest of them. They think it's funny, but it causes me and many others anxiety.
7. Antisemitism. Nazis everywhere, reinstated.
8. "Look at this idiot" + screenshot/quote type of posts. It's like being around bullies at school all over again.
9. Cancel culture. People look for your employers for the tiniest reasons.
10. "For you" algorithms. The cycle of negativity. Twitter wants to show you the posts that gain traction, and not in a good way.
11. Useless features that lead to clout. Who needs a view count?
12. Twitter Blue. All the features that would be useful are paid.
13. Things breaking down. Just look at Reddit's /r/twitter subreddit. Nothing works like it used to be.
14. Insecurity. If the simplest form of two factor authentication is a paid feature and doesn't even work properly anyway, what does that tell you about security? There are other concerns as well, because the security team is now gone. We'll see about that certificate later...
15. Mental health. Twitter triggers. A lot. Not a healthy place for a person suffering from Generalized Anxiety Disorder, or any mental health issue for that matter.
16. Elon Musk. The world's most spoiled child now owns the platform. There are so many things wrong in this picture that I don't go there here.
17. The verification mess. There's no meaning in verifying yourself any more. Other than you paid for the cesspool, that is.
18. Selling data. It's nothing new, but you should know the tweets are not yours. You create content for Twitter. You are the product. They sell your data.
19. No progress. Only thing Twitter has done is taken away features. The tech stack is slowly deteriorating as there are not enough people working on it.
20. Pissing on the open source community that has improved Twitter so much. Even I improved Tweetdeck once, before Twitter acquired it. Twitter under Musk killed all API access and shut down its open source projects. That means countless of web apps, integrations, apps and other cool things died. The biggest might be Tweetbot and Twitterrific. They develop Mastodon apps now. With the death of the possibilities for developers it's no longer possible to customize Twitter experience.
21. Heavy advertisement. Twitter force feeds you ads in between every third tweet. The ads can't be avoided now, because there are no third party apps.
22. Twitter does not care about accessibility on both user- and employee level. The company completely sacked a group focused on accessibility of the platform for disabled users. Remember Haraldur Ingi Þorleifsson?
23. So many good folks have already quit. About 10% of the people I find worthy to follow are on the Fediverse.
24. Centralization. As an open source nerd this is one of the reasons. You can't host your own Twitter. You don't own your data on Twitter. If Twitter goes down, that's it.
25. The post length. 140 was a statement, 280 characters is like "write more, but not enough".
26. Threads. "Top 10 bullshit things. A thread 
".
27. Uninteresting algorithm exploiting trends. No useful content. As an artist I've seen endless amount of those "Send me your latest songs!" and as a programmer "Are you on GitHub? Send me your profile!". Those people are not interested in you, they just fish followers and boosts from the algorithm that favors commented posts.
28. There is a better alternative. Come to Fediverse, join Mastodon.
29. Read the news about Twitter. You really want to support all that crap with a clear conscious?
30. You either have a private account behind a lock or completely public one. No middle ground. On Mastodon you can choose the visibility per post. You can also prevent your profile showing up in Google. When you know the Mastodon features, it's hard to go back.