What is the moral of the story "The Necklace"?

"The Necklace," by Guy de Maupassant, serves to prove the long-established point that money doesn't equal happiness. Mathilde Loisel, the story's main character, is so depressed by her lack of material things that she cannot show her face in public to her friends who are more wealthy than she. Even though she has a maid, a house, and furniture, as well as a loving husband, she is never satisfied. Forever thinking that she must have money and expensive things to feel fulfilled, Mathilde finds herself in a state of constant frustration.
When her husband is invited to attend a party by one of his colleagues, Mathilde is overwhelmed with self-hatred. She says that she cannot possibly attend, because she doesn't have anything appropriate to wear. Her husband uses all of his savings to buy her a dress that she deems suitable, but she is still not satisfied. She must have some jewelry to cover up the fact that she is not rich. After borrowing a necklace from her wealthy friend, Mathilde is content and feels like the most "beautiful woman in the room" while at the party, simply because of the dress and necklace that she is wearing.
Upon leaving the party, Mathilde realizes that the necklace is missing. Her husband uses his inheritance to pay for a replacement so that her friend will not find out, and they spend the rest of their lives working to pull themselves out of debt. One day, Mathilde meets her friend on the street and explains what happened, and she is told that the original necklace was not real. 
What Mathilde thought was happiness was merely created by having material things, which can always be taken away. Therefore, if one's happiness depends on money, it will be fleeting. It is important to recognize what one has rather than to ruminate on what one does not have.