The point about the cynical view however I disagree with. I don't think I have the correct words to explain this, but basically, unlike India, Korea and maybe to a certain point Japan, they distrust this kind of American, almost forced friendliness, cheerfulness and enthusiasm and see it as fake, which is very similar to how French, Belgians, Dutch or Germans feels sometimes (I know I did my first time around in California).
That's also the reason why out of all of Asia, I feel the best working with Chinese teams (Japanese too but I have more trouble with their English).
[Edit]: forgot the point about social shame: not untrue, but geographically limited to the more rural area in my casual observation. No one in Beijing takes themselves that seriously, but in poorer areas, pride and face felt more important.