It may sound cliche, but through Daisy Buchanen, Fitzgerald is trying top prove the old axiom that "All that glitters isn't gold." The life of the "old" rich certainly looks appealing on the outside, and Daisy is drawn to it. Who wouldn't want mansions, diamonds, travel, parties, expensive cars, and people who envy your lifestyle? Daisy wanted it so badly, that she gave up waiting for her "true" love (Gatsby) because she realized early on that he couldn't provide that lifestyle for her.
However, once "trapped" in this world, we find out that it isn't a happy place for Daisy. She is, frankly, bored. The most exciting thing she has to look forward to is a date on the calendar, and even that she misses:
In two weeks it'll be the longest day in the year.... Do you always watch for the longest day of the year and then miss it? I always watch for the longest day in the year and then miss it. (Chapter 1, pg. 12)
She doesn't even get pleasure out of being a mother, as she has delegated all those duties to a nanny so she can sit around being prima donna. But even she realizes that being a woman in this world may be glamorous, but it is certainly not fulfilling. In talking about her hopes for he daughter she says:
I hope she'll be a fool - that's the best thing a girl can be in this world, a beautiful little fool.... You see, I think everything's terrible anyhow.... And I know. I've been everywhere and seen everything and done everything. (Chapter 1, pgs. 17-18)
Finally, Daisy shows us how shallow these people are. After all Gatsby went through to get her, and after their passionate love affair, when he was in trouble, Daisy didn't even bother to contact him much less come to his aid.
Gatsby himself didn't believe [her call] would come, and perhaps he no longer cared. If that was true he must have felt that he had lost the old warm world, paid a high price for living too long with a single dream. He must have looked up at an unfamiliar sky through frightening leaves and shivered as he found what a grotesque thing a rose is and how raw the sunlight was upon the scarcely created grass. A new world, material without being real, where poor ghosts, breathing dreams like air, drifted fortuitously about.... (Chapter 8, pg. 162)