Jason, the hero, is among a rare breed of men. To him,

The idea of the great adventure was delightful [...].

Further, the narrator tells us,

High courage was necessary to travel, especially outside of Greece.

We see both play out in the text. There are a great many dangers that Jason and his men encounter: everything from actual sea monsters to supernatural beings to meddling gods and goddesses to greedy and sinful kings. Some of the men must drive the Harpies away, and even Hercules is lost when his armor-bearer is pulled underneath the water by a lusty water nymph. The crew must make it through the Clashing Rocks and avoid the warlike Amazons.

This myth also gives us a glimpse into the traditions surrounding hospitality to strangers. Travelers, the Greeks believed, ought to be offered especial privileges and were protected by Zeus himself. For this reason,

Only after the heroes had bathed and refreshed themselves with meat and drink could King Aetes ask them who they were and why they had come. It was accounted great discourtesy to put any question to a guest before his wants had been satisfied.

The king, obeying the laws of hospitality, does not even ask his guests' identities until after they have been taken care of and been able to rest for a bit. Once he learns of their identities, however, he becomes very angry. He thinks to himself, "'If these strangers had not eaten at my table I would kill them.'" Because he cannot kill them, as doing so would dishonor Zeus, he offers Jason challenges that he believe will have the same result. However, Medea helps Jason, as does Hera.

This is what makes Jason's betrayal of Medea so unbelievable later on. Having returned to Iolcos,

[...] Jason showed the meanness that was in him, brilliant hero though he had seemed to be: he engaged himself to marry the daughter of the King of Corinth. It was a splendid marriage and he thought of ambition only, never of love or of gratitude.

His infidelity and inconstancy costs him a great deal, however, because Medea—his thwarted lover—murders both his new bride and their own two sons.