I've never bad repped or No thanksed (<---lol don't even think thats a word), anyone before, my opinion is that if I don't like something someone has said ignore it, im not goin to do the rep/thanks on negative stuff incase that person thinks im bullying or picking on them. I'm happy to thank people but like I said, if I don't like it, I keep it too myself, I dont want to make other people feel bad or annoyed.
Just ignore bad stuff, it can't hurt you.