Hey its happened to me before, a couple times. I've had times where I forgot a controller was plugged in and my player's spinning while I'm confused till I find the controller upside down on the ground.
Hell one time I launched Battlefield 3 on PC to show a friend who usually played on console. I passed him a 360 pad I had plugged in, but it wasn't working. After trying to figure it out for five minutes, I pick up a USB NES controller, press left on the Dpad and it actually turned in game. Turns out the game registered the NES controller that was still hooked up for emulators as the default controller, ignoring the other one. I turned to him and jokingly said "You're going to have to play with this."