A story attains the status of myth when it is retold, and persistently retold, solely for its own sake. If I tell a story as a way of bracing up an argument or amusing an audience, I am not telling it for its own sake. To tell a story for its own sake is to tell it for no other reason than that it is a story. Great stories have this feature: To listen to them and learn them is to become their narrators.
