Manners are very important in our daily life. There are many different habits and customs among different countries. Here are the (thing) that a person with good education should do.
When you visit a Chinese family, you should knock the door first. Don't move before the host says "Come in, please." It is (polite) to take a seat before the host offers you. When a cup of tea (send) to your hand, you should say "Thank you." and receive it with two hands. Before (enter) a house in Japan, it is a good manner to take off your shoes. In England, if a visitor (eat) all the food, the host will be pleased with that.
If Englishman says "Come at any time." you shouldn't start fixing a date at once. in India, "come at any time" means "I want you to visit me." If you don't suggest a time at once, the Indian will think you are refusing the (invite).
Although there are many differences between cultures, there's one that is accepted (wide) in the world — smile.