Daisy is Nick's second cousin and the beloved of Jay Gatsby, a beautiful woman with an enchanting voice, a self-indulgent and irresponsible attitude to life and relationships, and an almost arrogant sense of self-entitlement. For Daisy, the world revolves around her - her wants, her feelings, her needs, and her resentments - and has, the narrative clearly suggests, ever since she was a girl. Nick's narrative comment about how she speaks seems to reinforce this idea, in that she seems to be deliberately pitching her voice at a place where people need to pay even closer attention to her. She is frustrated when her husband Tom seems to be moving out of what she clearly thinks should be his perpetual orbit around her, she barely mothers her daughter, and after some initial surprise, she clearly revels in being the center of Gatsby's renewed attention. Her response to the one party of his that he attends is very telling - she is not the center of attention and therefore does not have a good time. She, like Gatsby, is selfish in her love of others and in her self-love. Therefore, and also like Gatsby, she and her attitudes are important triggers for Nick's transformation, vivid jolts of the self-indulgent truths at work in the society to which he wants to belong and which, as the result of experiencing those truths, he eventually turns from.
