I love Doom, but what I've always respected about Carmack is the fact that he actively tries to get better by learning all the time.

This guy could easily have just learned C and called it "done", and no one would judge him for it. Instead, he's giving speeches talking about how cool Lisp and Haskell are and that he thinks functional is the way to go.

Whether or not he's right about that is a matter of preference, but I think it's cool that he's not content with "knowing enough".