Mathilde Loisel was born into a family of clerks, and—with no means of marrying up—she "let herself by married" to another such clerk. She seems like someone who ought to be of a higher class than she is, and this made her
as unhappy as though she had really fallen from her proper station . . . Natural fineness, instinct for what is elegant, suppleness of wit, are the sole hierarchy, and make from women of the people the equals of the very greatest ladies.
Her desire to transcend social class and her belief that her beauty and charm should have destined her for the upper class result in anger that she cannot achieve this. "[S]he felt made for "fancy dresses and jewels," and "She would so have liked to please, to be envied, to be charming, to be sought after." Though she has a husband who wants to make her happy, to provide her with the kinds of experiences she longs for, she is still unhappy because she doesn't have the material trappings of an upper-class woman. Her husband is even willing to give up a treat for himself for which he'd been saving, giving her the money to buy a beautiful dress. Still, she is unsatisfied because she has no jewels. Ironically, she says that "there's nothing more humiliating than to look poor among other women who are rich."
Sadly, she is wrong, and she feels the weight of her new and greater humiliation when she and her husband must work themselves to the bone to pay off the loans they take out in order to purchase a replacement necklace for Mathilde's friend after Mathilde loses it. She trades a life for one night of "happiness composed of all this homage, of all this admiration, of all these awakened desires, and of that sense of complete victory which is so sweet to woman's heart." After replacing the necklace, she "now knew the horrible existence of the needy." Had Mathilde been satisfied with her pleasing husband and her relative luxury (a nice flat, servants, and so forth)—in short, with her middle-class existence—she would never have "had [to] become the woman of impoverished households" that she does become after the party. She descends to the lower class as a result of her insatiable desire to ascend to the upper.