Kinship plays an important role in Chinese families. Because of the paternalistic system, the use of kinship terms in address is mandatory for the closest relationship; it is preferable for medium-distance ones; and it is usable even with strangers. The use of pronouns, which is quite common in many languages for addressing people of all different classes, has rather limited scope in China, in contrast to kinship terms. Because of the cultural and educational background, I prefer to address seniors with kinship terms or proper titles, rather than personal names.
When I was young, I was taught to address others who are older than me with kinship terms even though we do not have a blood relationship. When the person is female, the term of "jiejie" (older sister) is better than the term of "ayi" (younger aunt), and the choice of "ayi" is certainly better than the choice of "nainai" (grandmother), as well as "uncle" and "grandfather".
I have an aunt who is one of my mother's cousin. Although my aunt belongs to the same generation as my mother, she is two years younger than me, so I have to call her "aunt" when meeting her. Though it is the manners, personally, I feel so strange to address a girl who is younger than me "aunt", however, no matter I am willing to do so or not, I have to.
Unlike Americans, who usually seek the most egalitarian forms of address, Chinese usually seek to be told about their status relative to one another through the help of a mutual acquaintance, and they do so throughout their lives.
Actually, how to use proper titles to address people is a kind of art in China. Every time before I went to do an internship in China during vacations, my father always told me that I should address each employee in the company as "teacher". Because uttering the title "teacher" in China usually shows the speaker's respect towards the person who is addressed and makes the person feel that he/she belongs to the educated class and is someone with culture. What is more, if you call the person "teacher", he/she always becomes willing to help you.
Today, although I am studying in America, I prefer to utter the staff at FDU as "professors" if I do not know his/her status, even though we've never seen each other before. Besides I have been used to employing the title in universities, that is because in my mind, addressing them as "professors" is a kind of propriety and shows my respect to them, I do not believe that anyone would refuse respect from others.