Funny you should mention the close button for elevator doors. I'd never ever seen that used, almost as a defensive (or offensive?) gesture, before my trip to China. The second someone would come in after me they'd rush for that button, despite others heading to the elevator. What's with that? I didn't give it much thought at the time.

I'm also curious about references to Chinese natives being less than friendly. The younger people in particular were so friendly and helpful that, at times, I wondered if I was being set up for a scam (tea ceremony or some such). If I looked even slightly puzzled in a subway station, someone came by and offered assistance. Returning from one trip (early morning expedition to see the flag raising ceremony) I didn't have coins, just paper currency, and the only working machine on that side of the station needed coins. A security officer kindly helped out, offering me a coin for my bill.

I think problems and unfriendly people while traveling are often opportunistic. If you expect them, they'll find you. A smile and a friendly tone, even when there are language issues, can go a long way. And stress is never, ever a good thing to display. Stress implies that you've got a tough problem that someone may not be able to help with, or for that matter won't want to deal with.