What sort of post or comment gets you downvoted the most? Especially if you don’t think it’s bad behavior in the first place, or don’t care. Does not have to be on Lemmy, but we are here…
One of the good things about Lemmy IMO is that it’s small enough to see the posts that are unpopular. If you do “Top Day” on most channels, you cash reach the bottom, see what people here don’t like.
As far as comments, attempting to rebut the person who is telling me my post sucks, is what gets me into negative numbers most often. The OP is going to voite it down, of course, and nobody else cares, usually.
I’m not exactly sure what you mean by this but there are many different instances with many different rules. I’m sure you can find one that is close to your viewpoints.
Personally I don’t think it’s important to be exactly in line with your instance but I do find a subset of Lemmy.ml users noxious enough that I try to minimize my interactions with their instance.