It's boring, and dumb… I warned you.
I used to just post under my given name, but my surname is Polish/German and somewhat long. Others would butcher my name on purpose in replies to save keystrokes...
All the nicknames I had in school were either dumb, unwanted, or obscene.
Way back in the '90s when I sold PC's wholesale to mom-n-pop PC stores, (when there still was such a thing) my co-worker always thought it was funny whenever I said "So you'd like dual floppy drives?" to a customer configuring a PC, instead of simply saying "two". (dates me a tad even if I didn't admit to this being the 90's…)
He then assumed anyone with the name Andrew naturally had the middle initial of "J.", for Andrew Jackson, I guess... So he called me "AJ Dual". It was the only nickname I could think of, and for some reason, even though it was hardly ever used, even by my co-worker, it's in my head as a name I'll reply to automaticaly when I see it.
People think AJ Dual means all sorts of things, that I'm an Indian (the country) where Ayjay, AJ, Aijay is a common name. Or that I fancy myself the "dual gunslinger", or a dueler, etc. LOL.