What drives a banker?

I have been a banker for the last 11 years and have always felt that bankers in general are more driven than people in a lot of other professions. I know, I know the non-bankers will pounce on me as if I have committed a grave sin here by making this statement. Here, I am not talking about bankers you see in a retail shop. I am talking about guys that sit on the trading desk, that call on large corporate clients as part of DCM, corporate banking and other parts of financial markets. Let me know what you think.