How does character ambition form Of Mice and Men?

Steinbeck does a great job in exploring how the primary
motivations of different characters advance the narrative.  The opening section helps to
bring out two of these particular motivations in Lenny and George.  The latter's primary
motivation is to develop a means of making money, and enjoy the life associated with
it.  However, there is a competing motivation present to integrate a vision of a future
with Lennie.  The first section brings out how Lennie's hope of a farm is linked with
George.  When Lennie tells George, "I can go in a cave," if he was no longer a part of
George's vision of the future, George backs off of his own individualistic dreams and
shares the vision of the future that includes Lennie. In this dual competition of
ambition, the primary tension of the novel is present.  George's paradox of ambition
lies at the heart of the narrative.  Does one act for their own sense of being in the
world or seek to broaden it and include others in a more collective vision?  George
battles the demons associated with both throughout the novel, all the way until the end
when he takes Lennie's life.  The other characters in the novel all represent some form
of these motivations, but in the despair of the time period, Steinbeck might be making a
larger statement about where human ambition lies.  Individuals who embrace the shallow
pursuit of self- interested ends might be doomed to futility in their desire for
happiness.  Individuals who seek to embrace the more challenging pursuit of constructing
reality different than what is, embracing a more collective vision of the future,
represent  "the inarticulate and powerful yearning of all men."  Individual ambition
seems to be poised within this dynamic in the story.