In his anger, what does Biff attempt to force Willy to recognize in Arthur Miller's Death of a Salesman?

In Arthur Miller's Death of a
Salesman, I believe that Biff is trying to make his father see Biff—and life
in general, perhaps—more clearly and more accurately. Willy does not live in the
present, but in the past. And a great deal of that time is spent in discussion with
Willy's dead brother, Ben, while Willy has imaginary discussions with his successful and
much-admired sibling.

Willy always acts like Biff is just
getting out of high school when his options were endless…until he failed his math final,
failed to graduate, and lost his football scholarship. Willy ignores this and talks all
the time about how great Biff is and how he is really going places in the world. Biff's
anger stems from the fact that Biff is forever trying to address the issue, and Willy is
always brushing it aside. Biff finally confronts his father with hard
words:

You
were never anything but a hard-working drummer who landed in the ash can like all the
rest of them! ... I'm nothing, Pop. Can't you understand that? There's no spite in it
any more. I'm just what I am, that's
all.

Willy's refusal to see
Biff as he really is makes Biff feel worse than he already does about his inability to
be a success in life, and if Willy would accept Biff for who his son really is, then
Biff might be able to move on and make something of himself.