A hero's fatal flaw.

Achilles was the son of the sea goddess Thetis and the mortal Peleus, and the greatest warrior of Greece. In Homer's Iliad he stands as the hero of the Trojan War and the very embodiment of wrath. Later legend tells that Thetis, to render her son immortal, dipped the infant Achilles into the river Styx of the underworld. But the heel by which she gripped him never touched the water, and so it remained his single vulnerability. In the tenth year of the Trojan War, Achilles died when an arrow loosed by the Trojan prince Paris struck him precisely in that heel. From this myth the anatomical Achilles tendon took its name, and in 1855 the phrase 'Achilles' heel' appeared in English as a metaphor for a single, fatal weakness.

Hosadama (好事多魔) means that good affairs attract many demons (魔) — that the more smoothly a matter unfolds, the more unexpected obstruction and hindrance it tends to draw. The phrase appears often in Wang Shifu's Romance of the Western Chamber of the Yuan dynasty and in various Ming dynasty novels, especially in narratives where a hero and heroine, striving to seal a good union, are met with one obstacle after another. Here 'demon' (魔) was originally a Buddhist term denoting Māra, who obstructs spiritual practice. History confirmed this law again and again — internal division on the eve of victory in war, illness in a household just before a marriage, misfortune just short of passing an examination. Hosadama became an aphorism carrying the Eastern wisdom that one should remain humble when good fortune comes.