Daisy's first words are "I'm p-paralyzed with happiness."
There can be several interpretations of this. The first is that Daisy is merely saying what fashionable ladies say when they see relatives for the first time in years. She is attempting to make a casual, yet refined first impression. Simply, these words are empty, meaningless.
These words can also be interpreted ironically. She certainly seems paralyzed (remaining on the couch during the scene) but she is trapped in a loveless marriage with a man who carries on affairs while brutalizing her. She is also trapped in her personality, with no chance to grow or become anything more. In this way, her happiness (or at least contentment) could actually be holding her back. She sees no reason to try and change anything, and it foreshadows her doomed love with Gatsby.