Or are you too busy joining in?

Went to a wee shindig this Saturday night. Very mixed company, there was a kids contingent of guests, a sorta mid-20s contingent and a "really fucking old" contingent. We were all gathered in a room to watch a film that someone had made. Right afterwards one of the girls, probably about 7-8 years old fell while holding her pudding and her face landed right in it - it was pretty funny, people started laughing. Then it became very apparent that she was hurt and crying etc. The nice people had the decency to shut the fuck up and offer sympathy and a select few continued to laugh their braying fucking idiot laughter. Adults. Laughing at a young girl who was probably mortified. I know sometimes people have uncontrollable laughter, but this felt like faked or forced "uncontrolled" laughter.

Point of thread: I really feel smug when people I'm unsure if I really like that much give me a clear indication that I can file them firmly under "prick". What small things that people do cause YOU to be massively judgmental?