Nothing personal, and I don't know if people might take this too seriously, but I definitely hate people who leave negative comments on authors' fanfics. If it's something like constructive criticism or a warning, etc., I think it's really good, it helps to improve! But if it's something like "I hated this story," or "What kind of dialogue is that?" etc., things like that, I find it really sad. Especially for beginner writers, or those who comment these things in the first chapters of the stories. It's simply extremely demotivating... If you don't like it, I think you can just keep the comments to yourself and not read anymore, but don't go around commenting rude things, yk?