Hope & Dream

He does use them a lot. Aren't they related to the whole American Dream theme that runs through the novel?

he does it because the theme of the story is The american dream.

and everyone in the book had a different american dream.

I think he uses them because his entire existence is between reality and dream, because he writes about himself and reality when he creates fiction. Because these are the two things he most cares for. He hopes, dreams and fights to gain Zelda's love and to become a famous writer. The reality from the crack-up scares him, and he returns to dreaming and hoping.

These two words defines Fitzgerald best.