Death of a Salesman Psychological Lens

In Death of a Salesman, Miller focuses a lot on the psychological state of Willy. Through Willy, Miller expresses the toxicity that can arise from such a single minded focus on the American Dream above all else, including familial relationships. The key areas of Willy's psyche that Miller brings forth are his pride, denial, and insecurity. These three concepts are closely intertwined in Willy's actions.
In Willy's flashbacks, his true desires are revealed. When he is not fighting to preserve his pride, even his innermost consciousness still shows his insecurity.
WILLY: Bigger than Uncle Charley! Because Charley is not - liked. He's liked, but he's not - well liked (Miller 18).
Even in dreamland, Willy is reminded that Charley is doing better than he is. He can't escape it. His most hated idea in the world is that he, Willy Loman, is not number one. So, to make sure he can still consider himself as the most loved man ever, he must repeat the lie until he believes it.
When Willy talks to Bernard, Bernard reveals that something happened between Willy and Biff- something Willy adamantly refuses to acknowledge.
BERNARD: ... Did he have a talk with you then?
...
WILLY: What do you mean "What happened"? What's that got to do with anything?
Willy on some level knows what happened. He knows that his mistakes cost him his relationship with Biff, but he cannot acknowledge that. If he does, then he, Willy Loman, is a failure. That can't be true, so it must be the case that nothing happened in Boston. Bernard, who is no longer close to the Loman family, is more in touch with reality than Willy because Willy is buried in his own denial.

Willy compensates for his insecurity and uses his denial by forming a fortress of pride. He has constructed a self image of the most beloved and successful salesman who simply fell on hard times and then reinforced it so many times that he believes it. It's a coping mechanism. He always wanted that to be true, because he thought it would make him happy. When he didn't achieve it, he pretended he did, so he could justify pretending to be happy. While he may not know the difference on the surface, on some level he knows the extent of the self-deception, and it is ruining his life. Towards the very end of the play, Willy is contemplating suicide. As he does so, Ben approaches once more as a representation of Willy's pride.
BEN: He'll call you a coward.
WILLY: No, that would be terrible.
BEN: Yes. And a damned fool.
WILLY: No, no, he mustn't, I won't have that!
BEN: He'll hate you, William.
Ben is a representation of Willy's pride. Even though Biff shatters it in the end, here, Willy's pride is what stops him from committing suicide. His pride manifesting in Ben is an important detail to note as well. Ben throughout the play has been the most supportive of Willy. He treats him like an adult, calls him William, and gives the approval Willy so desperately wants. Through Ben, Willy is able to justify his pride in order to cover for his insecurity.
The psychological depth of Willy's character is a central part of Miller's play, and offers serious depth to how Miller views that style of life.