Anything but stupid one-upsmanship to no purpose.

In short, as a foreigner one is probably in a better position to learn than to teach (unless it's the English language or something).

Perhaps there's a middle way, which will necessarily require a certain awareness, not just of the situation as one sees it, but that communication, to work, requires awareness not only of what you want to say, but also of how you're going to be heard - otherwise you get miscommunication. Insults often work well when communication is no longer possible and there's nothing to do but fight - Last Resort Department, and most things aren't worth it.
As for changing things for the better, I think I've been changed for the better by many (not all) characteristics embedded in the Chinese sense of politeness. At any rate, if you're a foreigner somewhere, it would be ridiculous to imagine that you're likely to make any immediate dent in whatever you don't like locally, because you're always outnumbered by local habits. I'm sure this is as true in London as it is in Kunming.

Something about the build-up of electrical charges maybe - when big winds in the Med are about to start coming out of the Sahara (okay, different situation) it's been shown, apparently with scientific evidence, that people get jumpy & weird, & I think it's been traced to a build-up of electrical differentials between sky & land etc. Anyway, you might check out this electrical explanation, though I have no idea what to do about it.

@blue: I plead guilty. I just meant to say that Great Wall doesn't give me nightmares, and that a regular diet of the sweet crap would make me give up alcohol entirely, or simply switch to bai jiu and be done with it - an acquired taste, which after many years in China I have only half acquired - anyway, I can handle it, especially in good Chinese company (8 people around a big table with a really fine feast on it, everybody loosens up, knows where this show is going and it's all good). But I'm not about to criticize first-time westerners with bai jiu - took me quite awhile, and I'm not quite there.
Wine (e.g. - with real grapes) in China is another matter, but progress is being made - actually, rather quickly, if you can think back just 15-20 years.