The Megillah can be read on many different levels and in different ways. One of my favorite exercises to do with my students in Brooklyn College was to read the story of the four lead characters, separately, ignoring the plot threads of the other three. Each story can stand by itself. Haman is an interesting character. We know little of his motivations in the words of the Megillah, except that he hates Mordechai, seemingly for a personal slight. Haman’s plans become more and more bombastic. Maybe this is what the Talmud means when Haman made himself into an idol: it could refer to his inflated ego!
“Everyone should honor me! One guy doesn’t bow to me? Kill him! But wait, it’s below my dignity to kill just one person. Let me kill his entire nation! The queen invited me to a dinner party with the king. But there’s Mordechai again! Never mind petty. I’m going to hang him myself. The king wants to honor someone! It must be me! So let me wear the king’s finery! Oh no! The king wants to honor Mordechai! I have to lead him through the street! But at least I’m going to eat with the king and queen again. Oh no, Mordechai is the queen’s uncle, and his people are the queen’s people, and the king thinks I’m hanging his trusted servant Mordechai as a political statement. Now I’m being hanged on it!”
Had Haman done nothing, nothing would’ve happened, but the greater and greater he propped himself up, the further he could fall.