Willy has too much pride to accept Charley's offer of a job, yet Willy regularly goes to Charley when he needs money to make ends meet. Although Charley is incredibly patient with Willy, Willy gets exasperated with his neighbor because he doesn't seem to appreciate Biff's athletic ability when Biff is in high school. Willy even insults Charley on several occasions when Charley is just trying to make conversation such as when Charley asks Willy how to go about putting up a ceiling. A gifted carpenter, Willy just retorts, "A man who can't handle tools is not a man." Charley is never rude or abrupt with Willy. He even tries to tease Willy into a good humor from time to time such as when he tells Willy that "Ebbets Field just blew up." Willy, however, has little sense of humor.
Willy must respect Charley because Charley has a successful business, but Willy is reluctant to admit he isn't doing well until Howard fires him. Even then, though, Willy turns down Charley's offer of a job. Willy simply can't allow himself to be obligated to Charley for more than $50 or so a week because Willy is always hopeful that his business will get better---that is, until he makes the decision to take his life. That decision seems to be the only choice that he sees to help his family. Willy cannot understand how Charley, a man who doesn't seem to have what Willy thinks is necessary for success--personality--can be so successful.
Willy has far too much pride and does not want to take up his offer. He does not want to tell him that he has lost his job almost either. Willy hopes that his business will suddenly become a lot better when in fact there will not be any change. He is already asking for money from Charley and does not want this to continue.