It all started with teaching my 6 year old to play Mario. He kept running into the first enemy, then the first pit. He had to stop to jump. He was new to the game, and it's hard to be new. I had to teach him how to hold down the button to run, press the other to jump, and move all at the same time.
Early arcade games had the directional controller in the middle, with buttons on the left and right, so the player could control it which either hand. And then, as legend has it, the directional controller was moved to the left side, because most people are right-handed and would lose more games, thus bringing more quarters to those arcade fat cats.
Thus, I decided to right a great wrong in this world (at least for the original NES), and create a reverse controller!