If in the Republic of China, people of the same age can't call each other by their first names, this is a bit insulting.
One's first name can only be called by elders or family elders. In the past, people in China generally knew their seniority by their names, but now they don't know their seniority.
In addition, there are two kinds of names in China. One is that the elders call the names of the younger generation, which is the current name; The other is the name used in general interpersonal communication, which is the "word" in the romance of the Three Kingdoms, such as Zhuge Liang, the word Kong Ming, Zhuge Liang as the surname, Liang as the name, Kong Ming as the word, and of course, he also has the number: Wolong. . . The word "Zi" and "Hao" are used by peers or strangers. When swearing, they are basically called "Zhuge Pifu" or "Zhuge Liang". When calling themselves, they can call themselves "Liang" or "Kongming"
Of course, they are not so particular now.