Today's Penny Arcade is on The Big Bang Theory. (Well OK its more about some kind of game with The Big Bang Theory thrown in as a punchline, but work with me here.)
I know more than one person who watched an episode of Big Bang Theory and at some point said something along the lines of "I know it's funny, but I'm uncomfortable laughing at myself."
Sheldon is an exaggerated parody, but many of his foibles are based in real life tendencies.