Poor moderation tools at all levels (admin, moderator, user)
Lack of will to moderate at admin and moderator level
Replication of topics on multiple instances (two different lemmy instances with their own /c/technology - one too busy to keep up with, the other just a lone person posting links every so often)
Low effort content dominates some places making it difficult for an individual to find interesting content (see 1 and 2.user)