I learnt a few hard facts whilst here in BJ:
1) Whatever impression you have about the population of Beijing, dispel it! It's 10 times more massive than you think.
2) They still do spit on pathways. The local men (and women sometimes). But they apparently have improved lots.
3) There is no such thing as personal space here. Your personal standing space, and sometimes breathing space is always being enroached on. And we are talking about shoulder to shoulder, buttocks to buttocks!
4) Beijing can probably set the Guinness record for squeezing the most number of people in one train cabin. Try taking the subway at peak hour - this is when you see the most skilful of them all plonking themselves into the train however freaking cramped it is.
More to add on... till laters.