So, I've decided it's story time.
For starters, the username "imnotyourdude" is not, in fact, myself telling you that I am not your dude. The user name comes from a story back in my middle school years (roughly 7 years ago), and I have been using the name as a joke (and of course as an honorific to whom I am not their dude).
It was a hot summers day when an unnamed friend and I decided to ride bikes to a local convenience store to pick up a drink to quench our thirst. I was over at his house, so naturally, I didn't have my own bike accessible to me, so I had to ride his little sister's Disney princess bike. The bike was about 2 sizes too small, and on top of that I wasn't wearing a helmet (who wears helmets anyways) because my friend didn't own any spares.
So, we were riding down the street when a police car pulled up in front of us, causing us to stop. He got out of his car, and we instantly recognized him. It was the asshole cop the entire city knows: Officer Gonzalez. This guy is literally the definition of a douche bag cop, having broken up multiple street hockey games and screaming at children for no apparent reason (or something incredibly stupid). This guy clearly thought he was the shit, and as such, decided to pull us over.
As soon as he got out he sent a sharp stare directly at me, and walked over and put his hands on my handle bars.
Gonzalez -"Your bike is too small for you son, and your not wearing a helmet."
Me -"Sorry, I didn't have a helmet, and we're just riding down the street."
Gonzalez - "You know, it's illegal to ride with out a helmet! I am 36 years old, and I still wear my helmet! You could easily fall off that tiny bike!"
My friend - "Dude, sorry, calm down."
Gonzalez - "I AM NOT YOUR DUDE! I AM OFFICER GONZALEZ AND I AM THE LAW!"
Anyways, that's as far as you need in the conversation to get the point. So afterwards, we couldn't stop laughing about the I AM NOT YOUR DUDE quote, and made it an inside joke amongst ourselves. One day, we were playing some CS: Source, and kept changing our names to random stuff, before eventually I made mine "imnotyourdude" (it was the only thing that would fit), and it generated so many lulz it stuck forever. Thus, my username stems from that story.