What does the Odyssey teach about Greek literature?

Homer's The Odyssey teaches many things about Greek literature; perhaps the first is its enduring influence on Western literature. The hero's journey literary archetype arguably comes from the travels and travails endured by Odysseus.
In the epic poem, Odysseus also functions to communicate the character traits ancient Greeks thought valuable: courage, adventurousness, intelligence, and loyalty. Odysseus's faults function to caution against the traits of hubris and dishonesty.
The themes in The Odyssey show us that their literature was meant to be instructive. Its complex story offers lessons about the need for—and rewards of—piety, camaraderie, loyalty, family, and hospitality.
The Odyssey came from the oral tradition in the eighth century BC and was not written down for centuries afterward. The endurance of its story evidences the timelessness and universality of its themes and characters.