If you have watched the famous The Big Bang Theory series, then you could have remembered the iconic line of Sheldon Cooper. Our fanart Big Bang Theory I'm Not Crazy Sticker features this hilarious line of Sheldon Cooper when his friends question his sanity. When Howard accused Sheldon of being insane for wanting to use artificial intelligence and animatronics to build a new friend to replace Raj, Sheldon replied that he wasn't insane and his mother had him tested. So began Sheldon's habit of answering questions about his mental state by saying his mother had him tested.