Wanting vs Needing

(this post contains Mockingjay and Harry Potter spoilers)

Some writers create dossiers about their characters – what they look like, what breakfast cereal they like best, what star sign they are. It doesn't really work for me. Instead I ask myself two simple questions:

What does this character want?

and

What does this character need?

For a good story, the answers to those two questions must be different.

Let's go back to our old friend Harry Potter. Luckily for us, there's a chapter in the first...