On a train today there were a couple of late teen girls in front of me, and after the (female) guard had been round to check tickets, I heard one of them make a joke about the guards haircut resembling a bird's nest. When I took a sneaky look a minute or two later I realised the one who had made the joke had a trendy piece of headwear covering most of her hair.
AIBU to think you shouldn't mock someone else's haircut if you aren't showing your own? (Not that you should anyway).
YABU - It was just a joke between friends
YANBU - It's not nice and hypocrisy