I was got on a train to find a well dressed middle-aged woman yelling at some teenagers that were laughing at her, and making threats etc. No-one did a thing and it started escalating and she began to look like she was in real trouble. At this point the brain starts to say that she needs help and these lads need chasing off as she's under threat and they are going to attack her.

Very fortunately I waited and watch for a while as I then realised that she probably had mental health problems. The teenagers were just talking amongst themselves, and she assumed a whole lot of things had been said and was out of her seat and was the one posing the threat. They were actually alarmed and shouting back a little to frighten her off (and to look tough in front of their peers), but to onlookers it appeared a group was threatening a woman on her own.

Anyway it was all resolved peacefully. I certainly learned something about not assuming things based on looks and that someone that appears to be a middle-aged office worker can just go off the deep end.

Had one of those lads gone to court over it, I suspect they'd have been made to look like they were the aggressors.