How does Psychology help business leaders?

The most important way psychology can help a business leader is through self awareness. From Lucretius to Shakespeare to Freud, the importance of self understanding in becoming an effective leader has been a consistent theme. One way to increase self understanding is to ask your self not how do I see myself, but "how do others see me?" It is through the mirror of others that we can begin to understand ourselves. What method do you practice to increase your understanding of yourself?