I think whether they mean it or not, saying mean or nasty things when upset is not really okay.
I think it could be both and depends on the person. Personally when I get mad enough I'm truthful
It's both for me. Me and my partner got into it badly one time, and I told him I hated him multiple times that day, but I don't. I just hate certain things he does
My husband and I are both very hard headed and often have this issue during arguments, we will both say things that we don’t mean. We always apologize and do whatever to make the other feel better but neither of us have ill intent, just get heated
They are saying what they really mean.
Depends on the kind of people they are and the environment they grew up in. My husband grew up in an environment, where his parents would make shit up about him to make him feel less than where is my parents would over exaggerate my negative qualities to make me feel less than. Until we both worked to be better/got help that’s how we handled anger