Why and how does Biff eventually reject his father's dream of success in the business world over the course Death of a Salesman?

Willy Loman teaches his son Biff that the accumulation of
wealth is the ultimate measure success, and that one can get by on charm and good looks.
He spoiled Biff, leading him to believe that he could behave any way he wanted.
Unfortunately, this all unravels when Biff discovers Willy is having an
affair. In one moment, his world is shattered. Although he plays into
Willy's schemes to make money throughout the play, behind every action is the resentment
and anger he has built up against his father. After discovering the affair, Biff rejects
his father’s offer to convince the math teacher to let Biff graduate. Biff is betrayed
by his father's emptiness and selfishness, and he can no longer idolize Willy or believe
in his version of the American Dream. This spirals into a life of failure and drifting,
which reflects Willy's own failures in business, and the tragedy of his never achieving
the American Dream. Because they never achieve their ideal success, Biff recognizes his
failure to live up to his own standards and the way he has hurt his father to get
revenge for his betrayal.