In China,we always smile is the traditional custom,when we gave it to the old man,must want to use things is not for the old hands pass,rude.In young children,we compare the big man to do the elder of style,can't teach bad children for a child,not a dirty word,when to other people's house,we want to master give priority to,can't follow one's inclinations,have to the host's permission tamper with things that will make host is very angry,we should always smile at people,