1) Lending and borrowing are more matters of principle in the West than in the East. Things borrowed in the West are definitely expected to be returned, whether it is fifty dollars or merely a friend's pencil.
2) Don't Be Curious
It is impolite to be curious about the private affairs of others, such as age, salary, religion and marriage.
3) Thanks for Gifts
When some one gives you a present, it is very impolite to neglect thank him for it.
4) One Hand Only
In china we use two hands when giving something to a person, or when receiving it, if we want to be very polite. In the West this would seem awkward and impolite.