Different countries have different customs. When you are in different countries, you should follow their customs.
In China, it's impolite to talk when eating dinner. And you're not supposed to start eating first if there are older people at the table.
Very often people who travel to the United States forget to tip(付小费). It is usual to tip waiters, taxi drivers and porters who help carry your bags. Waiters expect to get a 15% tip on the cost of your meal. Taxi drivers expect about the same amount.
In England, make sure to stand in line even if there are only two of you. It's important to respect lines there. It's a good idea to talk about the weather. It's a favorite subject of conversation with the British.
In Spain, it's a good idea to have a light meal in the afternoon if someone invites you for dinner. People have dinner very late, and restaurants are not generally open until after 9:00 pm.
In Saudi Arabia (沙特阿拉伯), men kiss one another on the cheek (脸颊). Your host may welcome you with a kiss on both cheeks. It is polite for you to do the same.
In Japan, people usually give personal or business cards to each other when they meet for the first time. When a person gives you a card, don't put it into your pocket as soon as you get it. The person expects you to read it.
Don't forget to be careful of your body language to express something in conversations. A kind of body language that is acceptable in one culture may be impolite in another.