Repetition plays a large role in defining the motifs of any novel and this novel is known in particular for its use of motif to support theme. One of the novel's central themes is dreaming and pursuing hopes.
The character of Jay Gatsby is closely associated with the idea of dreaming and of hope (hope beyond the norm, beyond the average person's capacity for belief, for faith, for fulfillment...). Gatsby's dream in particular is given literal play and symbolic play in the novel.
Nick discusses the story Gatsby tells him about his vision of a ladder to the sky. Often, Gatsby's hopeful intentions regarding Daisy are discussed. Furthermore, Gatsby's nature and demeanor are defined by this tendency to dream and this leaning toward hope.
[Gatsby had] an extraordinary gift for hope, a romantic readiness...