Why are most chinese people rude?

First of all, i'm not racist. i'm a chinese myself (living in HK) and most people i've met in mainland china are rude and less... civilized. people there just push you instead of saying "excuse me", a lot spit, they shout and point everywhere etc. I've just returned from shanghai and this waiter accidentally spilled coke on me and walked off as if nothing happened. she saw what happened and shrugged it off. wtf. i'm sure there are really nice chinese people in the PRC, ive met a few but im just appalled by chinese mannerisms.