Any fan of The Big Bang Theory knows that Sheldon is full of mysteries. In the past season or so we've, finally, been privy to the reasoning behind some of his curious behavior, like why he always knocks three times whenever he's confronted with a closed door. Well, now another of the character's big secrets has been revealed and it was completely unexpected. After years of being driven everywhere by his friends, much to their repeated irritation, Sheldon finally revealed to Amy that he's actually had his driver's license for a whole two years. What?!