Why is Poseidon angry with Odysseus?

In The Odyssey, Poseidon is angry with Odysseus because Odysseus blinded Poseidon’s son, the Cyclops Polyphemus. After Polyphemus trapped Odysseus and his crew in a cave and ate some of the men, Odysseus escaped by getting the Cyclops drunk and driving a sharpened stake into his eye. At first, Odysseus cleverly protects himself by telling Polyphemus that his name is “Nobody.” But once he escapes, his pride gets the better of him. He calls back across the sea and reveals his real name so that he can claim the glory for defeating the Cyclops.

This moment changes the rest of Odysseus’s journey. Polyphemus prays to his father Poseidon to avenge him, asking that Odysseus should either suffer greatly on his journey or never make it home. Poseidon answers that prayer by sending storms, wrecking Odysseus’s ships, and delaying his return to Ithaca for many years.

Through Poseidon’s revenge on Odysseus, the poem shows the danger of letting a desire for glory overtake self-restraint. Odysseus’s clever escape from the cave is a triumph of intelligence, but his decision to boast his name is driven by pride and the desire for fame. That single moment of vainglory turns a successful escape into a long punishment from the gods, as Poseidon’s anger becomes the force that repeatedly blocks Odysseus from getting home.