Like other ethnic groups, the Tibetans have their own conventions and customs. Tibetans are sanguine, lively, en-thusiastic, honest, frank, kind and humorous. They love to make jokes and enjoy themselves. Family members, friends, colleagues, and neighbors like to get together to celebrate weddings, births, moving to a new house or festivals. These are all times for talking, drinking, joking and laughing.

　　Although joking at a friend's house is permitted, one should think twice and pay attention to whether relatives are present. There are two kinds of relatives, lineal and collateral. The former includes siblings with at least one parent in com-mon, aunts, uncles and their offspring; the latter are people with the same surname, blood relations in the Tibetan's view. Northern Tibetans are especially particular about the sur-name. They treat all with their surname as family members, addressing them similarly, whether they are close or remote relatives.
　　n get-togethers, one should check for the presence of his or others' relatives before making jokes. And one must not use swearwords or make strange gestures. Dress should be proper, with no part of the body exposed except the arms.
　　People of the same age can joke freely. They will invent wild stories about past experiences and future plans it is just good fun and should not be misunderstood. In fact, though they love to joke, Tibetans are extremely cautious and careful when it comes to making decisions.
　　Four surnames are important in a person's life: father's, father's mother's, mother's, and mother's mother's. If two per-sons' surnames coincide at any level, they are relatives. This rule is not limited to the father's surname: if one person's mo-ther's surname is the same as another's father's surname, the two are also relatives.
　　Related men of the same age group can call each other brother. When men and women with the same surname meet, however, they should be demure and cannot consider love or marriage. Such a rule was set by their forefathers and handed down over thousands of years. Nobody can alter or violate it. Genealogy is traced from parents and grandparents back six to eight generations. People with the same surname but from different families are considered to be linked by blood re-gardless of the generation.
　　Most people observe these traditional rules. However, because some people do not pay much attention to surnames or are mistaken about them, they make jokes uninhibitedly or even fall in love and get married. In this case, relatives and friends will condemn them. If they are close relatives, they will be regarded as heretics who have soiled the family's good name. People will deride and insult them, making them feel too ashamed to show their faces.
In making friends, Tibetan stress being "well-matched." A friend need not have similar economic status, but he must have an immaculate surname. The surnames of blacksmiths and butchers are generally thought to be unclean, although they are not related to blood ties. On the whole, Tibetans are very loyal to their family name.
　　If a stranger moves in, it is necessary to know his sur-name. A person who does not know his own surname will suffer discrimination. It will be difficult for him to gain a foothold in the community and he cannot expect to mix and make friends. A Tibetan will never change his surname, wherever he goes, whatever happens.
　　When visiting relatives or friends, chatting or joking, no matter how simple the occasion, how lively the atmosphere, the tone is always set by one factor a person's surname.