In fairness, they were rude first. But I am possibly the least confrontational person in the world (with strangers, at least) and I’m not sure what came over me. Bunch of laddy blokes, early 20s and clearly fairly well-oiled, being generally loud and obnoxious. Leering and commenting at some teenage girls who initially tried to ignore them then sensibly moved carriages. Everyone else ignoring them. I eventually got sick of it and went to move carriages as well but that involved walking past them. As I did so one of them said something along the lines of he’d happily fuck me even though I’m fat 
and others all laughed. Normally I’d just ignore but for some reason I turned round, intending to channel Mumsnet with ‘did you mean to be so rude?’ But what actually came out was ‘is there any particular reason why you’re being so rude today or are you always just a bunch of total cunts?’ 
Audible gasp from someone else in carriage, followed by rather ominous silence so I scurried off. Now sitting at the other end of the train shaking, mortified and hoping they don’t come to find me 
.