Why do we have nicknames?

Answer 1

We have nicknames to define our personality and to show a sense of friendship or affection.

unless it is an offensive nickname

Answer 2

Nicknames are often used as a way to show familiarity, affection, or to differentiate people with similar names. They can also be a form of endearment or a way to create a sense of closeness or camaraderie within a group. Nicknames can also serve as a shorthand way to refer to someone in a less formal manner.