Comments saying "first" don't really bother me much. I just ignore it XD
Got a comment that says I promote bullying because there's a side character who happens to be a bully and is calling another character names. LOL
I also don't like it when they mention a diff webtoon. There's one that says they dropped another webtoon for mine, and as flattering as that sounds, they don't have to declare it at all since I don't like seeing other webtoons being treated this way (I know I wouldn't like it if somebody also says this about my webtoon in another webtoon's comment section)
Also when your characters are constantly being compared to an anime character, or another webtoon character (usually featured ones, and sometimes discover/canvas ones that I'm not familiar with). It's usually because of appearance and attitude.
This doesn't bother me much, I find it funny actually, but it gets annoying when it's being said over and over lol.
Rude and hate comments in general~ I don't understand why people have to leave these kinds of comments. It's as if they enjoy bringing others down, instead of helping creators improve.