Courtesy of the act is an act of courtesy,it is very useful in our lives.Etiquette in different countries are different.For example,when talking with others close to the behavior stops.Asia and Europe in the feelings of people are different.Even in China,and some manners in different places are different.For example,in his room can be loud.However,in public places it is extremely impolite.And friends have to whisper when they talk.In addition,in public places can not laugh or make a very loud sneeze