Scene 8 is significant because it is begins to build the tension that erupts in Scene 9, ultimately leading to the final confrontation between Willy and Biff in Scene 13.
For the first time in his life, Biff attempts to address his life as it really is. Waiting for Oliver makes Biff realize he has been living a lie. All this time, Biff has directed his anger and resentment toward Willy because he considers him a "fake." However, Biff is his father's son, just like Happy. He too creates a favorable past for himself — or an unhappy childhood — in order to justify the course his life has taken. As a result, Scene 8 is a turning point for Biff. He consciously chooses reality over fantasy. He would rather deal with the facts, as strange and disturbing as they may be, than reinvent events to suit his purpose.
Scene 8 is important for Willy because he is also truthful about his situation. For once he does not attempt to sugarcoat his job or his success for the boys. However, Willy contradicts his own willingness to accept reality as he continues to force Biff into a lie. Willy cannot allow Biff to fail because that will only magnify his own breakdown. He constantly interrupts Biff while he is talking for two reasons: to prevent Biff from telling the truth and to interpret the events as he wants them to be. Happy contributes to Willy's fantasy by contradicting Biff each time Biff tries to be honest. So as Biff makes an effort to finally achieve order by admitting the truth, Willy and Happy likewise attempt to create order by concealing the truth.
