What happen if you are rude to Chinese?

All Chinese are individuals. They have different personalties. Some may just shrug it off, some may scold various profanities both in English and Chinese(Cantonese insults are one of the worst in the planet), some may choose to beat the crap out of you. Those from the local gangs or triads may take a cleaver/weapon and maim you on the spot or threaten your family.

However, Chinese are generally more tolerant, especially if they are living in a minority community (America, Europe etc.). They will most probably just ignore it unless you press the issue (In which case, it will make you a xenophobic racist piece of sh@t).

Hope that answers your question :)