If you look at what anger accomplishes and the damage it causes, no disease has cost humanity more. You'll see mass murders and poisonings. You'll see people accusing each other back and forth. You'll see cities destroyed and entire populations wiped out. You'll see rulers sold into slavery at auctions. You'll see torches thrown onto roofs and fires that don't stay within city walls but spread across whole regions with the flames of war. Look at the ruins of the most famous cities — you can barely tell where they once stood. Anger destroyed them. Look at deserts that stretch for miles with no one living there. Anger made them empty wastelands. Think of all the leaders that history remembers for their terrible fates. Anger stabbed one in his bed. It struck down another even though he was a guest under sacred protection. It tore another apart right in the courthouse, in front of a crowded forum. It made one die by his own son's murderous hand. It made another have his royal throat cut by a slave. It made another stretch out his limbs on a cross. And so far I'm only talking about individual cases.
Next, if you choose to view its results and the mischief that it does, no plague has cost the human race more dear: you will see slaughterings and poisonings, accusations and counter-accusations, sacking of cities, ruin of whole peoples, the persons of princes sold into slavery by auction, torches applied to roofs, and fires not merely confined within city-walls but making whole tracts of country glow with hostile flame. See the foundations of the most celebrated cities hardly now to be discerned; they were ruined by anger. See deserts extending for many miles without an inhabitant: they have been desolated by anger. See all the chiefs whom tradition mentions as instances of ill fate; anger stabbed one of them in his bed, struck down another, though he was protected by the sacred rights of hospitality, tore another to pieces in the very home of the laws and in sight of the crowded forum, bade one shed his own blood by the parricide hand of his son, another to have his royal throat cut by the hand of a slave, another to stretch out his limbs on the cross: and hitherto I am speaking merely of individual cases.