A so-called 'sense of humour' can be a double edged sword. They are fine when THEY are calling the shots, but when the boot's on the other foot they are often hyper-sensitive and easily 'butt-hurt'. A bit like those 'jolly fat' people who turn all dark and nasty after a couple of drinks
I used to have a 'friend' who was reknowned for her 'sense of humour' (actually I think everyone was scared of her). She was really quite cruel and sadistic, and if anyone 'dared' to bite back she would be all, 'chill out man, where's your sense of humour?' hoot hoot. Of course, it was a completely different story on the rare occasion that she encountered anyone with an equally nasty and quick tongue.

