Strange start to the day

There was a tall, suited, bald black man sitting to my left on the tube this morning gesticulating wildly at himself and mouthing words at his reflection in the windows at the opposite side of the carriage. He may well have been schizophrenic. Noone reacted to this as if it was troubling or unusual. There's minding your own business, but this lack of reaction practised by Londoners is still pretty freaky to me.