In the United States,very few people have lifelong fixed employment contract with an employer but in 1912,1935 and the next may in a very distant place.
To a new place,everything is new,most of my friends have such relations.Related to this is a friend of stability.The Chinese people is a close friend of the social network,because China traditionally emphasized "righteousness",so the relationship between the relative stability of friends.The so-called "at home by their parents,went through friends," "friends marks for" all reflect Chinese friends concepts.Americans living changes and changes in the power,and therefore the relationship between the relatively loose friends,some degree of stability is low.Only in a considerable number of friends to send Christmas cards are in the form of a link.