what does Emily learn about the way people live their lives when she returns to the living ?

A constant theme in the play is the human tendency to miss the simple joys of their lives. Throughout the play, characters learn of opportunities and experiences missed while paying attention to other, less important things. For instance, Emily tells George in the second Act that she was always receptive to the possibility of loving him, but that he was too busy with baseball to notice her; George realizes at that moment that the thing he had always wanted most, Emily's love, was available to him all along. And in the third Act, when Emily returns to her twelfth birthday, it agonizes her to see how rushed life was, how seldom they took stock of their happiness; she begs her mother to pause for a moment and just look at her, look at how happy they were. In the end Emily realizes that living people don't understand how fleeting and precious their lives are.