The theme in the short story "The Necklace" deals with greed. Madame Loisel is greedy. She has a comfortable life. She has a servant and food on the table, but she desires more delicate meals. She is not content with what she has:
Although she does not have a lot of money, Madame Loisel may be justly characterized as greedy. Her life is comfortable enough to afford one servant, but she wishes for several. She has plenty of food, but she dreams of "delicate meals."
Madame loisel is lovely, but she does not feel lovely because she has no fine jewelry. She "suffers incessantly" due to her lack of fine, luxurious things in her life. She brings hardship on herself because she is not satisfied with the life she has.
There is also a theme of appearance versus reality. While Madame Loisel is beautiful, she does not experience the reality of being beautiful. She is pretty and charming, but she longs for the reality of finer things in life:
Madame Loisel is beautiful, but she is not content. She has the appearance of beauty but not the reality (or truth) of beauty. She is pretty and charming, but she is also unhappy with her lot in life and believes that she deserves more. Living modestly with her husband before the ball, Madame Loisel believes she is suffering a terrible injustice by having few luxuries.
Again, Madame Loisel brings on her own suffering because she does not appreciate what she has. She has a doting husband and he works hard to provide for her. Still, she complains and dreams of the finer things in life.
Another evident theme is the presence of class conflict. Madame Loisel desires to be upper class. She had moderate means but she desires all the extra things in life. She is discontented with being middle class. She really has no idea what poverty is until she loses the necklace and has to work extra hard to pay for the replacement. Madame Loisel should have been contented with what she had. Now, she really understands poverty. Ironically, she learns to be content in her poverty stricken situation.