Most nicknames are bequeathed onto the nicknamed by others. They are not the ones who typically come up with their nicknames, nor are said nicknames natural and fitting from the word go. When I was in middle school, I bequeathed one of my best friends with the nickname «Beef.» Why she still talks to me after that, I have no idea. But for some reason, because I was so insistent and it was objectively amusing, she embraced the Beefy side of her and even incorporated this nickname into her Instagram handle.
Nicknames often serve the function of making one’s name easier to say quickly or easier to pronounce. Beef’s real name is Remelee, and going from three to one syllable was a real time saver. Sometimes, it’s just a display of affection. I call my friend Aurora «Rory» sometimes because I have so much love in my heart for her, and a niche nickname fortifies that.