Want as Desire and Need
Looking at outer and inner wants.
You can't always get what you want
But if you try sometimes, well, you might find
You get what you need
— Rolling Stone
In his book The Anatomy of Story, John Truby says that a character has both desire and need.
Desire drives the story. It is:
what your hero wants in the story, his particular goal.
But your character also has an even deeper want: their need. Need is:
what the hero must fulfill within himself in order to have a better life. It usually involves overcoming his weaknesses and changing, or growing, in some way.
This need develops from your character’s weakness, which occurs because:
something is missing within him that is so profound, it is ruining his life.
For Truby, desire and need are “intimately connected.” The needs of a character will drive their desires.
A character may need to protect his family, so he has the desire to threaten the villain when they come too close.