On a train yesterday. I’m on my way to the toilet but a rather large young gentleman is just moving between carriages. There is obviously not enough room for him to come past me so I move into the gap between seats to let him through. He thanks me and I nod, common politeness should be acknowledged after all, but he then thanks me again, Ok, maybe he didn’t see the nod. As he come past me he says angrily “fucking smile can’t you?”

Yes I can, thank you, but why should I?