Willy recalls his sons' teenage years as an idyllic past. What evidence can we find to show that the past is not as idyllic as Willy imagines it?

You might have hints of this less than ideal past in the fact that Biff has not made anything of his life since that time. It makes one wonder, hmm, was the past as good as it seemed? There were, however, some more specific points. In Act I, part 2, Biff took a football from school without permission, a sign of irresponsibility (or worse). However, it is in part 3 of that act that the signs really pile up. Biff wants Bernard to cheat for him (definitely a bad sign), he's too rough when interacting with girls (a worse sign), and Linda ends up crying.