How did you pick your username?

Some people have unique user names. What is the reason you picked that name?

I picked my name charizard274 because back in 2009 when i had my Windows XP i'd go by that name, never liked pokemon though just the name.
Honestly, I don't remember why I picked this name clearly.
As far as I remember, my best friend used to call me clara. Well, she likes heidi and in that her favorite character is clara. Also, my favorite color is violet. Well, I like all shades of purple and violet.
So, by combining those two words, I came up with my username. People often mistook my username with Chevrolet though :)
My nickname in our house is Jing. I picked my nickname from the instagram that I have, adding the letter "J" to a word that is common in this generation.
Honestly I pick my username because I want to remember my very especial someone. My nickname is jun while my partner is rose that is why I came up to an idea to just mixed them to make junrose123 in the sense that I came up to that username in an instant. That is why there is the number 123 to signify how fast I made that username. It is really a cool and username that I was able to make, it always reminds me of my partner whenever I will see or heard about it.