For me, it was the toxic circlejerk (admins/mods as well) low quality content getting upvoted while high quality submissions not getting much attention/buried and obvious privacy issues.
Open-Sourse at the first moment. But Lemmy offer so much more then only being a Reddit in Open-Source.
US centrism. I tried to unsub from the worst offending communities, but I still am unable to scroll down a page without seeing something obviously only relevant to the US or tainted by yankee culture. posts and comments assume everyone is USian and anyone who isnβt is treated like a foreigner.
It made my mood worse, affecting my daily life. So I cut down, and now I barely go there at all.
I still use reddit as it has content lemmy doesnβt.
But yeah I think there is a lot of bots/shills that manipulate the conversation on reddit that doesnβt really happen on lemmy. This will happen on lemmy too if it gets big enough.
Federation is also cool. If lemmy does end up full of bots/shills then someone could make a new instance with some new rules that help to reduce the number of bots (e.g. answer some questions about a post to comment or something).