Daisy is The Great Gatsby's most enigmatic, and perhaps most disappointing, character. Although Fitzgerald does much to make her a character worthy of Gatsby's unlimited devotion, in the end she reveals herself for what she really is. Despite her beauty and charm, Daisy is merely a selfish, shallow, and in fact, hurtful, woman. Gatsby loves her (or at least the idea of her) with such vitality and determination that readers would like, in many senses, to see her be worthy of his devotion. Although Fitzgerald carefully builds Daisy's character with associations of light, purity, and innocence, when all is said and done, she is the opposite from what she presents herself to be.
From Nick's first visit, Daisy is associated with otherworldliness. Nick calls on her at her house and initially finds her (and Jordan Baker, who is in many ways an unmarried version of Daisy) dressed all in white, sitting on an "enormous couch . . . buoyed up as though upon an anchored balloon . . . [her dress] rippling and fluttering as if [she] had just been blown back in after a short flight around the house." From this moment, Daisy becomes like an angel on earth. She is routinely linked with the color white (a white dress, white flowers, white car, and so on), always at the height of fashion and addressing people with only the most endearing terms. She appears pure in a world of cheats and liars. Given Gatsby's obsession with Daisy and the lengths to which he has gone to win her, she seems a worthy paramour.
As the story continues, however, more of Daisy is revealed, and bit-by-bit she becomes less of an ideal. Given that she is fully aware of her husband's infidelities, why doesn't she do anything about it? Because he has money and power and she enjoys the benefits she receives from these things, she is willing to deal with the affairs. In addition, when she attends one of Gatsby's parties, aside from the half-hour she spends with Gatsby, she has an unpleasant time. She finds the West Egg nouveaux riches to be tedious and vulgar, an affront to her "old money" mentality. Another incident that calls Daisy's character into question is the way she speaks of her daughter, Pammy. "I hope she'll be a fool," she says, "that's the best thing a girl can be in this world, a beautiful little fool." Clearly, she has some experience in this area and implies that the world is no place for a woman; the best she can do is hope to survive and the best way to do that is through beauty rather than brains. Later, in Chapter 7 when Pammy makes her only appearance, Daisy treats her like an object, showing her off for guests, suggesting Daisy's lack of concern for her child. Daisy's life revolves around Daisy, allowing Pammy in only when it's convenient. Clearly, in real life Daisy isn't all the way Gatsby remembers — but blinded by his dream, he cannot see the truth.
Although Daisy seems to have found love in her reunion with Gatsby, closer examination reveals that is not at all the case. Although she loves the attention, she has considerations other than love on her mind. First, she knows full well Tom has had affairs for years. Might this not motivate her to get back at him by having an affair of her own? Next, consider Daisy's response to Gatsby's wealth, especially the shirts — does someone in love break into tears upon being shown an assortment of shirts? For Daisy (and Gatsby too, for that matter) the shirts represent wealth and means. When Daisy bows her head and sobs into the shirts, she is displaying her interest in materialism. She doesn't cry because she has been reunited with Gatsby, she cries because of the pure satisfaction all his material wealth brings her. He has become a fitting way in which to get back at Tom. When Tom and Gatsby have their altercation at the hotel in Chapter 7, Daisy's motivations are called into question: Her inability to deny having loved Tom speaks well for her, but at the same time, it suggests that her attachment to Gatsby has been purely business. Tom also knows that after Daisy realizes Gatsby is not of their same social circles, she will return to Tom for the comfort and protection that his money and power bring.
Although Daisy's true self comes out more and more each time Nick encounters her, her final actions help show what she has been really made of. When she hits and kills Myrtle Wilson, and then leaves the scene, readers know (as poor Gatsby still does not) that she is void of a conscience. Perhaps all that white that has surrounded her isn't so much purity (although Gatsby, of course, would see it as such), but perhaps the white represents a void, a lack (as in a lack of intellectualism and a lack of conscience). To Daisy, Myrtle is expendable. She is not of the social elite, so what difference does her death make? To add insult to injury, as if she hadn't betrayed Gatsby enough already, she abandons Gatsby in his death. After killing Myrtle, Daisy returns home. She and Tom resolve their differences and leave soon thereafter, moving presumably to another city where they will remain utterly unchanged and life will continue as it always does. Daisy, although ethereal in some qualities, is decidedly devilish in others.