In my culture (Thai), I put my given name first and then my family name (inherited from my father), like in most of the west, but actually my name of formal address is my first, given name, and my family name is hardly ever used except as a differentiator. [1]
In Vietnamese culture, I believe the given name is also the name of formal address, yet the family name comes first as in China and Japan. Hence Nguyen Anh would be called "Anh".