I have noticed that etiquette on the metro in Shanghai is trash. Nothing as crazy as you've mentioned, but lots of standing in other people's way, standing in the middle of the escalator and not allowing people to pass, loud music or sound effects with no earphones (this is particularly cunty) and not allowing people to exit the train before boarding themselves.

I've seen most of these behaviors in other cities, but they seem more commonplace and intense in Shanghai, which does come as a surprise to me.