Obligatory "not today" disclaimer: actually fucked up over two decades ago, but found out today.
At the dawn of theinternet, I made an account on imgur. I figured (correctly) that I wasn't going to use it often enough for the username to matter much, so I just went with the first part of my email adress and a number four times.
Turns out that there is such a thing as nazi number code and it's never a good idea to use an even number of 8s for usernames when you're not a nazi.
TL;DR: Didn't know about nazi code, accidentally selected an imgur username ending with the equivalent of a double Hitler salute
my brother's email ends in '88' because it's his fav number. he likes it because it looks like two sideways infinity symbols. he's had his email too long and it used it for too many accounts to (easily) switch to a new one. so you're not the only one lol
My birthday is 8/18 (18.8 if you aren't in North America), so I have a few accounts that end 818. I legit had someone ask me, in all seriousness, if I was an idiot nazi who screwed it up.