4 ideas
Goodwin, the dreaded ruler of the Emerald City, was really an ordinary circus balloonist from Kansas whose balloon blew into the Magic Land. The inhabitants took his arrival from the sky as proof of sorcery.
Everyone entering the Emerald City must wear locked green spectacles, supposedly to protect their eyes from its brilliance. The spectacles are what make ordinary glass and stone look like emeralds. Seen this way, a place's prestige can come from the filter imposed on its observers rather than from the place itself, and the rule that the filter can never come off is what keeps the illusion alive.
Villina's magic book says Ellie can go home only if she helps three creatures achieve their dearest wishes. This makes her private goal depend on serving others. A quest built this way turns each companion's need into a step toward the hero's own escape, so helping others becomes the only route to getting what you want.
Goodwin gives the Scarecrow bran mixed with pins for brains, the Tin Woodman a silk heart stuffed with sawdust, and the Lion a drink for courage. Yet each had already shown cleverness, compassion or bravery on the road. The token works because it gives the owner permission to believe in a trait they had already proved through action.