Every hero needs both an inner and outer problem. In developing fairy tales for Disney Feature Animation, we often find that writers can give the heroes a good outer problem: Can the princess manage to break an enchantment on her father who has been turned to stone? Can the hero get to the top of a glass mountain and win a princess’ hand in marriage? Can Gretel rescue Hansel from the Witch? But sometimes writers neglect to give the characters a compelling inner problem to solve as well…They need to learn something in the course of the story: how to get along with others, how to trust themselves, how to see beyond outward appearances. Audiences love to see characters learning, growing, and dealing with the inner and outer challenges of life.
– Christopher Vogler, The Writer’s Journey