Willy Loman is a dreamer of epic proportions. His dreams of material success and freedom ultimately dwarf the other aspects of his mentality to the point that he becomes completely unable to distinguish his wild hopes from rational realities in the present. Happy and Linda also are extremely optimistic, but they maintain their ability to distinguish hopes from reality. Biff more than any other character struggles against the force of Willy’s dreams and expectations.
Dreams function purely as a form of self-deception in Death of a Salesman.