Odysseus goes against ancient Greek attitudes and values by his arrogance, hubris and pride.
After he ignores his shipmates' pleas and entreaties to come back to the ship, Odysseus' men have to confront terrible consequences. Not only does he not come back from the Cyclops island but he also screams out his name to the giant Polyphemus foolishly believing he's in control of his interaction with the Cyclops. He even boasts he is a 'raider of cities' and a native from Ithaca further proving his arrogance and pride.
For Greeks, hubris was considered a sin and also blasphemous since it was seen as a way to challenge the gods.by equating men to them.