My blocklist is 30~40 users long. [For reference, my blocklist in Reddit reached 400 or so.]

To keep it short, I typically block people who, egregious or consistently:

• show lack of reasoning, even if I agree with the conclusion
• misrepresent what others say
• take things off context to judge them, even if I agree with the judgement
• vomit lots of “hard” certainty on things that they cannot reasonably know (e.g. the others’ emotional states over the internet)
• engage in passive aggressiveness (note that I tolerate some clear hostility, just not pass-aggro)
• show clear signs of sealioning (e.g. “I don’t understand” + misrepresentation of what someone else said)
• tell others shit like “trust me” = “I expect you to be a gullible piece of rubbish”

Note that “egregious or consistently” are key words here. Like, I’m not going out of my way to block someone out of a brainfart; this is not some sort of petty revenge, it’s just removing from my sight people who I believe to not contribute with my overall Lemmy experience. I also don’t take issue when people block me, for whatever reason they might have.