I've posted on here in the past about my habit of adding quitters to my list of blocked chess.com members. I also will block anyone who's rude. (E.g., one guy made some remarks in his native tongue, a language unknown to me; let's just say that Google Translate left me with the impression that he wasn't congratulating me on a well-played game.) This apparently ensures that I'll never be paired with them again. Seems to work pretty well.
In order to do this, I click on the offender's username, which takes me to his/her profile page, and then cut & paste the username into my blocked list. (I actually often visit the profile pages of my opponents anyway -- naturally, I'm even more inclined to do so if the person is nice, which most chess.com members are.) Very often on the profile pages of annoying people we can find comments posted from other site members, comments that are, shall we say, not necessarily in a flattering and friendly tone. "You're a loser," "You're pathetic," "Get a life," etc., etc. Very often the comments are months or even years old.
I don't marvel that some people are annoying (I've posted about that in the past as well), but why on earth would someone leave hateful comments on his/her profile page? Are these people proud of the fact that they irritate others & want the whole world to know? Are they just too lazy to delete the remarks?
Just a fascinating oddity of human behavior.