During the first part of this scene, Amanda's conduct does show that she knows how to entertain and that she is not overly distracted by the lights going out. She is also very careful to use this as an excuse to get Tom into the kitchen so as to leave the gentleman caller with Laura.
The scene between Laura and Jim O'Connor gives us our first view of Laura as a person. Suddenly, she comes alive as an individual, unique and different, but with her own charm that goes much deeper than the superficial gibbering of Amanda.
Note that as the scene progresses, Laura rapidly gains confidence in herself and begins to lose some of her shyness. She relaxes enough to show Jim her glass menagerie, a collection that she treasures and that she would not readily show to just anyone. It is then that she explains her preference for the unicorn, which like Laura, is different from the other animals; its uniqueness makes it Laura's favorite. Symbolically, the unicorn here represents Laura's own self. She is also different and unique. But she, like the unicorn, doesn't complain about being lonesome or unique, and like Laura, the unicorn is the most delicate of all the animals in the collection.
After looking at the collection, Jim proposes to Laura that they dance. He is still trying to build up her ego and to prove to her that she is not as different as she thinks herself to be. In other words, he is trying to break through to Laura; But the dance is used also as the method by which the unicorn is broken, and Jim's clumsiness can also break the delicate Laura.
