At work, I use my left hand for the mouse to save my right wrist from daily rigors. Then I use the right hand for games at home. I could just imagine going up against someone in an RTS game and stealing the lines from The Princess Bride.
opponent: You’re not a very good player
me: I’m aware of that
opponent: Then why are you smiling?
me: because I know something you don’t know. I am not left-handed! [switch hands]
opponent: You’re still losing really badly.
me: I know. I’m not very good at RTS games.