I would have to say that Odysseus' worst trait is his excessive pride. When he and his men finally escaped from the Cyclops, Polyphemus, the only name the Cyclops had for the man who blinded him was "Nobody". Odysseus couldn't resist telling Polyphemus his real name once he and the crew were beginning to sail away. He wanted Polyphemus to know who it was that had blinded him. Not only did he give the Cyclops his name, the arrogant jerk told him where he lived (Ithaca) and who his father was (in case there were any other guys in Ithaca named Odysseus). What Odysseus didn't realiize was that he'd just blinded the son of the Sea God, Poseidon, who wasn't about to take the injury to his family lightly. Polyphemus prayed to Poseidon that Odysseus would never make it home to Ithaca, but if he did, then it would take a long time and he would arrive on a foreign ship; also, his crew would all be dead, and there would be trouble waiting for him at home. Odysseus' big ego led to this prayer which foreshadows all the major events of the epic.