You can't give yourself a nickname. It's simple: one of life's defining rules. I tried it once but "Big Jack" never caught on. My friends call me "Saddle Bags" instead. My dad reckons he once knew a guy who answered only to "Turd" and though I can't say for certain, I'm guessing Turd didn't offer that up himself.
Still, better to be labelled by your friends than to be nicknamed by Donald Trump. His steady teasing of his Republican opponents has served to belittle seasoned politicians more than any policy debate possibly could.
"Low Energy" Jeb came to define Jeb Bush's campaign. "Little Marco" proved prophetic as Rubio's campaign withered and died, and "Lyin' Ted Cruz" sounds like a character in a 1950s western.
Still, Cruz will be happier with his Trump moniker than with the nickname bestowed on him by fellow Republican John Boehner. We've all seen politicians get nasty but Boehner's description of Cruz as "Lucifer in the flesh" should be considered from the perspective of Cruz's core support group.
Among evangelical Christians it doesn't get worse than Satan himself.