I am telling you from experience, you.are.wrong.
So you can either think about it and change your opinion, or you can wilfully persist in being irrationally judgemental and w.r.o.n.g.
For instance, say you are super-pissed at your girlfriend. She has hurt you immensely.
You can go mad with hurt-rage, and, knowing that she is self-conscious of her yellow teeth, make a snide remark about her yellow teeth, even though HONESTLY, in your true, real heart, you think her yellow teeth are cute, adorable, and sexy.
BUT, since you know that that will really "get her", you "lose it" and make a snide remark about how ugly her yellow teeth are, even though you don't really feel that way,...JUST because you know it will hurt her as badly as she hurt you.