Why teach? I've said why. Gevlon has his reasons.
The point: We're not all that different. Both of us want to make the virtual world just a little bit better. We want to teach the noobs. Why? Because it makes a better world for us. Maybe I have a touch of altruism, but ultimately, I am like most people: I am self-serving.
Fewer noobs mean more good players, so go out and teach. Use whatever method you find works. Though you might want to avoid being a horrible douchebag; that tends to make people defensive.