Why do achilles and agamemnon become so enraged with each other?

Agamemnon's demand humiliates and infuriates the proud Achilles. The men argue, and Achilles threatens to withdraw from battle and take his people, the Myrmidons, back home to Phthia. Agamemnon threatens to go to Achilles' tent in the army's camp and take Briseis himself. Achilles stands poised to draw his sword and kill the Achaean commander when the goddess Athena, sent by Hera, the queen of the gods, appears to him and checks his anger. Athena's guidance, along with a speech by the wise advisor Nestor, finally succeeds in preventing the duel