I think that Amanda's characterization is significant to the thematic development of the drama in a couple of ways. The first is that her obsession with who she was, the nostalgia of the past she demonstrates, is representative of how the theme appearances vs. reality is illuminated. Williams deliberately gives Amanda traits that prevent her from fully embracing who she is in the present in light of what she was in the past. Amanda's crumbling present with her daughter, son, and the husband who abandoned them is in stark contrast to what her past was. In showing how Amanda struggles to acknowledge this, there is a sense that Amanda lacks the understanding to see the present in the future without her clinging to the past. At the same time, I think that Amanda's character as one clinging to Tom and demanding that he accept the duties she has placed on him ties into how the theme of desire colliding with duty develops over the course of the drama. Amanda's insistence that Tom's duty is to the family, a family that drove her husband away and will soon do the same to Tom, is something that is both a part of her character and something that drives the drama to its final scene while helping to establish its exposition. In this, Amanda's character traits become significant to the thematic development of the drama.