From The Big Bang Theory Wiki
Sheldon considers himself to be a superior form of human being.
I'm clearly too evolved for driving ... have you ever wondered why my little toes and lateral incisors are significantly smaller than the average for someone of my size? Well, those are indicators that I'm farther along the evolutionary scale than the average human. I'm not gonna go so far as to say that I represent a distinct new stage in humankind--you know, a "Homo novus", if you will. No, that's for anthropologists to decide. But I am convinced that the reason I cannot master the plebeian task of driving is because I'm not meant to ... I'm meant for greater things, like unraveling the mysteries of the universe ...
See also Sheldon 2.0