One of the most difficult character traits to work on is humility. Not only is it considered the most pervasive of the all of the middos, it is the most misunderstood. On one hand, we are obligated to appreciate the greatness of the human, yet on the other, we must remain humble.
One technique to help identify the trait and its pathology is to see it in its extreme. Using the story of Megillas Esther as a backdrop, and particularly some of foibles of Haman, we are able to witness arrogance in its extreme, and thereby find its cure: the understanding that I am a human.
This is a highly recommended Shmuz for working on the trait of humility, as well as a good preparation for Purim.