[A lot of people do. It's not great but it really does seem to be part of just. Being human. Or at least sentient.]

I don't really think any situation, shitty or not, is an excuse for shitty behavior. I think it explains it but I would also hope if it was pointed out to someone that they were being, well, shitty that they'd be able to learn from it?

That said I've probably done my fair share of asshole moves in my life. I think everyone has.