True characters can only be expressed through dilemma … A character is the choices they make over a lifetime.*
Robert McKee

The witch is the shadowed projection of Dorothy’s own resentment and hostility taken to its ultimate form. In all great initiatory experience, a person meets the shadow or evil within and must understand and conquer it before one can return home again.**
Jean Houston

Jean Houston suggests that Dorothy’s character is separated and
displayed in two lives in the Wizard of Oz –
Our dilemmas in life both help us to see ourselves and
to become who we want to be, and the fact that
this can keep happening over a lifetime means that
we should not give up on ourselves or on others:
Compare Dorothy in the beginning of the movie and
in the final scene –
So we use every day.

*Robert McKee‘s newsletter: Who Is Your Character, Really?;
**Jean Houston’s The Wizard of Us.