Some people are just aggressive cunts, they think somehow it makes them "hard", really pay it no mind, if he wants to go through life like that leave him to it. He will one day come across someone who he shouldn't have fucked with.
Never had it happen punting but yeah had it happen often, I don't bother engaging with it, nothing to be gained from it.

Agree I would have felt a bit sorry for the girl he was seeing if that's his general demeanour. He could be a softy and he just suffers from a severe case of resting bitch face.

I find myself judging others based on my own observations, I try not to and do find myself questioning my 1st impressions, but it's human nature. 1/3 of people will dislike you straight off the bat without you doing a single thing. Again, don't sweat it.