What is the importance of the flashback scenes in the play "Death of a Salesman"?

In Arthur Miller's Death of a Salesman, the flashbacks are crucial scenes that reinforce the play's emphasis on questionable nostalgia and Willy's own distorted vision of what constitutes the American Dream. Indeed, the flashback functions to show how Willy Loman has always valued a warped idea of the American Dream and brilliantly juxtaposes the harsh reality he exists in the present day of the play. The flashbacks tend to have a rosy tint to them; everything was better in the "good old days," and Willy has a nostalgic affection for these times. However, there are obviously dark points lying just beneath the surface of these flashbacks, and they eventually surface as the play continues.

One of the key figures in Willy's flashbacks is his brother Ben. Uncle Ben ventured into Africa, into the so-called "jungle," and became incredibly wealthy from diamond mining. Willy has always regretted not joining his brother in his adventure, and this illustrates Willy's idea of the American Dream. Willy's expectations are unrealistic; one cannot get by simply by being "well-liked" as Willy likes to think. Therefore, the flashbacks are essential scenes that give viewers an insight into Willy's flawed character.