Polyphemus (the Cyclops) and King Alcinous
The greatest contrast among the secondary characters in The Odyssey is between the Cyclops, that wild race of cannibalistic one-eyed giants, and the Phaeacians, the civilized, hospitable folk who encourage Odysseus to tell of his wanderings and who then sail him home to Ithaca. These are best represented by Polyphemus (sometimes simply called "the Cyclops") and King Alcinous.
The one-eyed giants are barbaric. Fortunately for them, their homeland is so lush that they need not cultivate crops. Although they are effective herdsmen, they have no interest in the usual trappings of civilization. Polyphemus and his fellow brutes have no laws, no councils, and no traditions of civility or hospitality. When Odysseus' curiosity leads him to Polyphemus' cave, his men want to raid it and leave. Odysseus insists on staying to try the hospitality of the owner, a decision that ultimately results in the death of several of his men.
A son of Poseidon and nearly as powerful as the gods, Polyphemus scoffs at the concept of hospitality and welcomes his guests by devouring two for supper. Although powerful, Polyphemus is not particularly intelligence. He is easily convinced that Odysseus' name is "Nobody," leading to confusion when Polyphemus later tells his fellow giants that Nobody is harming him. Odysseus easily gets Polyphemus drunk, blinds him, and escapes by riding underneath the rams that the blinded giant turns out to graze in the morning.
King Alcinous and his fellow Phaeacians, on the other hand, are decent, civilized, and kind. They are known for going out of their way to return a helpless stranger to his homeland. This tradition exceeds even the generous welcome that we often find in The Odyssey and is consistent with the Phaeacians' devotion to Zeus, protector of lost wanderers and champion of suppliants. Alcinous' people excel at seamanship and communal activities, but they are not aggressive militarily. They once lived dangerously close to the warlike Cyclops but moved to avoid trouble. Odysseus is comfortable among the Phaeacians. It is disturbing that Poseidon is allowed to punish them for their tradition of returning wayfarers to their homelands.