In Arthur Miller's Death of a Salesman, what are three flaws that lead to Willy Loman's death?

As Act I of Death of a Salesman
begins, and we watch and listen to the careworn Willy Loman, we become painfully aware
of his multi-faceted hamartia, or tragic flaws. They include three
of the following: First, as the audience gradually shifts with him into his past - an
imaginary golden age of success in sales and a son, Biff, shining with promise - we
become aware that he is mentally deranged; he is being crushed by the weight of routine
and failure. Second, as he confesses to Linda that he is not liked; or pleads with Ben,
his brother, to show him the way to success; or begs his employer, Howard, to give him a
desk job for which he is not qualified we become aware that he is burdened by
self-doubt. So burdened, in fact, that he constantly lies about his actions, talents,
and abilities.  Third, habitual lying has brought him to a delusional state. For
example, not admitting that Biff is failing math leads Willy into a delusion he shares
with his son - that the math teacher, Mr. Birnbaum, has something against him. This, in
turn, leads Willy to take a few moments to enjoy Biff's mocking of the math teacher's
mannerisms. It is during this time that Willy's mistress reveals both herself, and
therefore to us the delusion in which father and son are immersed. For Biff, by the
conclusion of the play, the escape from delusion is a hard-won self-awareness; for
Willy, the escape is death.