Willy Loman is the unsuccessful, imaginative salesman which the play is focused on. He is very child-like and this can be noticed in his lack of reality. He believes he is the best salesman ever and thinks that everybody likes him. Children often have these ideals. They often think they are the center of the universe and haven't had any experiences in their short lives that would bring them back to Earth. Willy has chosen to selectively ignore reality and live in his own world. Willy isn't a good salesman and isn't well liked. He is a failure and refuses to accept that fact, even with the pleadings of his favorite son. Willy is also and stubborn and competitive man. He has always been competitive with Charley, his friend and has tried to exceed him in everything. Charley is successful and has a son who also has become successful.
This is the ecact opposite of Willy. Charley offers Willy a job when Willy gets fired. However, Willy refuses because he is so stubborn. Charley is always nice to him and has given him money so that Willy can pretend he is getting a paycheck. Charley also gives him advice that would help him become successful, but he doesn't take it because that would mean conceding that Charley is successful and he isn't. Another example of his stubborness is the fact that he refuses to accept the fact that his philosophy of business (becoming successful by appearance and being well-like) doesn't work. He grew up being told those ideas but times have changed. Society has become more capitalistic. Willy refuses to adapt and cannot accept a business system based on capitalism. He does realize to a limited extent that he doesn't really have a place in society. He is part of a dying generation. Thus, his stubbornness and refusal to accept reality are major parts of his character and eventually lead to his suicide.
Willy is also a loving father, but in a dillusional way. He has two sons, Biff and Happy. He loves both of them but Biff is his obvious favorite. He has great aspirations for Biff and tries to live vicariously through him. Biff doesn't follow his fathers lead and in many ways is a victim of his father's delusion. Willy wants so much for Biff as any parent would want for their child. He realizes he is a failure as a parent because he instilled the values Biff has. He commits suicide in hope that Biff will get the insurance money and then become a successful man.
Willy and Biff have a conversation that reveals both of their true feelings and causes a change in Willy. He realizes that his son does love him. He also now knows that he is a failure in business and as a husband and father. When he lost his job he also lost his will to live. Though he still lives in a dream world, reality is hitting him. He continues to have delusions about his dead brother, which shows that he still isn't truly in touch with reality. His brother tells him to come to the forest and find the diamond. Willy takes the car and commits suicide. He became a victim of his own delusions.
I felt sorry for Willy Loman and wished that he hadn't been so stubborn. He did have the potential to become a great businessman, he just needed to adapt to the industrialized world. Willy was a weak man. He wasn't a strong enough person to accept the reality around him. His weakness as a man also allowed him to commit adultery. He instilled values in his son that reflected him. He tried to live vicariously through Biff and ended up destroying any chances Biff had to become a successful businessman. He was also so weak that he committed suicide. He couldn't face reality and succumb to negative forces. He never tried to change and thus in many ways deserves what happened to him.