How people get nicknames:
Recipient of a third-degree burn in front of witnesses. IE, "I won't take that shit from a man dressed like a ghostbuster"= "Gostbuster" or "Buster"
A distinctive personal feature or quirk. IE, "Have you noticed how that new guy is always eating bell peppers?" = "Peppers", or "That chick has a massive forehead" = "Forehead".
An embarrassing thing you said or did. IE, "Did you seriously call Dale "Dad"?" = "Junior", "Baby boy", "Sport"
A game of name-mutation telephone. IE, "Donny Clyde" = "Bonnie 'n' Clyde" = "Bonnie" = "Bon-bon".
Irony. IE, calling a tall person "short stack" or a particularly dour person "sunshine".
A 'wrong place wrong time' one-off incident. IE, "He spilled oil on his pants and had to borrow a pair that were way too big and Jim saw him with the waistband pulled up to his nipples and called him 'Parachute'"
A batman-style origin story but not in a cool way: "One time she hit a deer with the company car and when she called the boss to tell her she was crying so hard we thought she was dying" = "Bambi"
The incredibly rare 'admiration' nickname, bourne only once a millennia under the light of the blood moon: "We saw him lift a truck once so now we call him 'iron man'"
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