King Agamemnon is a greedy person along with his stubbornness. This explains that when the King captured Chryseis, the father of Chryseis wanted to claim his daughter in exchange of an enormous money but the King refused. The father prays to Apollo to punish the Achaeans. Apollo sends a plague in Greek Camp which caused the death of many soldiers. The king was forced to give back Chryseis to her father.
When the king's maiden, Chryseis, was gone back to his father because of greediness the king wanted a replacement for Chryseis. The king wanted Briseis in exchange with Chryseis which dealt the argue with Achilles.
It all started because of the King's greediness that made Achilles to have revenge which caused the bigger war between the achaeans and the trojans. The war may have not happened if the King only returned Chryseis properly and not made achilles gone mad.
This happens to all of us in our life. Because of our greediness it makes our life more miserable. For example, your teacher told you to tell to your classmates that he will treat the class for occassion or someting but you only told it to your friends so that you would eat more. When the class knew that you didn't told it to them and your friends do not knew that the whole class is the one to be treated not only them so they would blame you for your greediness. The class may treat you bad because of what you've than. Greediness would not do anything good for you.