For me, it’s the lack of diversity in opinions. IDK about you but I’ve only seen people from here and lemmygrad.ml, and nearly everyone is pretty far left. I’m not having a big problem with it, but the site is very, umm, single-minded.
And this mind is particularly hostile to my ideas
Personally, I’ve been generally happy with Lemmy overall. There are some minor UI quirks, but overall it’s been great and I really like the community here. It’s refreshing to have a forum that’s politically left.