The customs (习俗) in different countries are rather different. If I have dinner with a Chinese host, he always puts more food onto my plates as soon as I have no food. It often discomforts me greatly. I have to eat the food even if I don't want to, because it is considered bad manners(没礼貌) in the West to leave one's food on the plate. I have already noticed that when a Chinese sits at an American's dinner party, he very often refuses the offer of food or drink though he is in fact still hungry or thirsty. This might be good manners (有礼貌) in China, but it is not in the West at all. In the US it is impolite to keep asking someone again and again or insist on (坚持) him accepting something. Americans have a direct (直接的) way of speaking. If they want something, they will ask for it. If not, they will say "No, thanks". When an American is fed with beer by the host, for example, he might say, "No, thanks, I'll take some diet Pepsi–cola if you have it." That is what an American will do. So when you go to the US, you had better remember the famous saying, "When in Rome, do as the Romans do".