I was messing about in a fighter simulator (previous milenium) and the game told me I did an insane move. It sticked, so I called myself TheInsane. In an online game, that nick was already in use, so I got the suggestion to take TheInsane1... nah, there is only 1 answer to everything, so I added that. It stuck since then. I got me the matching domain in '22.
I'm using KoffieNu as well, as it matched my domain koffie.nu (proud owner since '98), mainly on mastodon, git and some dutch lemmy instances.