In Arthur Miller's Death of a Salesman, Willy gives the boys to believe (when they are younger) that they can achieve anything and that they deserve it. He compares them to Bernard:

...Bernard can get the best marks in school, y'understand, but when he gets out in the business world, y'understand, you are going to be five times ahead of him...Be liked and you'll never want.

Willy won't listen when Bernard warns that if Biff doesn't improve his math grade, he'll flunk out of his senior year and lose his football scholarships. This is exactly what happens. Bernard obviously has what it takes to make his way in the world, but Willy is not realistic at all, and misleads his sons into believing that the world will accommodate them. 

As youngsters, the boys think that Willy is every wonderful thing he says he is. The boys kid and joke with Willy like he's one of their friends. When Willy makes fun of Bernard after the young man leaves (trying to get Biff to study), the boys agree with Willy:

WILLY: Bernard is not well liked, is he?

BIFF: He's liked, but he's not well liked.

HAPPY: That's right, Pop.

When Willy comes up with fantastical dreams for the three of them, the boys never doubt what their father says says. When Willy asks Biff if he's nervous about the big game coming up, Biff says:

Not if you're gonna be there.

Biff's admiration is apparent.

As the boys become young men, Willy cannot understand why they have not been more successful. Willy is stuck in the past and is delusional about how good his good old days really were. Willy "misremembers" his own success. When they are young, Willy fosters his sons' futures on false dreams of accomplishments that Willy never actually had.