Why do George and Lennie recite their dream?

In
,anddream of one day owning their own piece of land, of being
self-sufficient, and of never having to work ever again for anybody else.

Throughout the story, Lennie repeatedly asks George to recite this dream. For example,
in the opening chapter, Lennie implores George to "Tell me ... Like you done before."
George then recites the dream, repeating the words "rhythmically as though he had said them
many times before." He tells Lennie that they have "a future" and that they will
look after one another. He also tells Lennie that they will have "a little house and a
couple of acres an' a cow and some pigs" and that they will "live off the fatta the
lan.'" This is George and Lennie's own version of the American Dream. When we first hear
George and Lennie talking about this dream, we feel hopeful for them.

Later
in the story, George mentions this dream again. He says that he knows "a little place
(they) can get cheap." Lennie insists that George tell him more about the place, and George
tells him that "it's ten acres" and has "a little windmill ... a chicken run ...
orchard ... a place for alfalfa and plenty water to flood it." When we hear about George
and Lennie's dream the second time, we become even more hopeful for them. Their dream seems so
close and so possible.

At the end of the story, however, after Lennie
accidentally kills Curley's Wife, we realize that the dream that was so close will never come
true. The fact that the dream has been repeatedly recited throughout the novel, each time
building a more and more palpable sense of hope, makes the loss of that dream at the end of the
story all the more tragic.