Due to difference in history, culture, religion, etc, there are particular customs and etiquettes in different countries and people. A same gesture or motion means different things in different countries. For example, the thumb and index finger forming a circle with the rest three fingers pointing upwards, in America, it means OK. However in Brazil, it is an impolite gesture. In China, we erect our big thumb to show admiration to something or somebody, but in Iran, the same gesture humiliates people. It can't be easily used. You can erect your thumb to appreciate an Iranian. In our country, we shake our head to disagree, but it is the opposite in Nepal where shaking heads means very happy or in favor of. You know he is very happy if he shakes his head. The world is big with complicated customs. You need to understand them if you want to get along. we Chinese need to have some understanding of customs worldwide to deal with them. In addition, some countries have taboos. For instance, Japanese avoid number four because number Four sounds similar to death, which means bad luck or unfortune. In daily life, no four gifts are given. There is no fourth seat in theater. Christian avoids number thirteen. Especially, there are no parties on days where Thirteen falls on a Friday. If these customs are not paid attention to, it would mislead to disrespect or embarrassment. When visiting a country or attend activities first time, we should do more understanding and observation. We can minic others if we don't know what to do.