In "The Necklace," what values drove Mme Loisel desire a piece of jewelry and to go to the ball?

I don't think I would call them "values", but what drove her to wanting to go to the ball with a jewel to wear was her discontentedness with her life. She was probably in the upper middle class of society, but she was never looking at what she had in life, she was only looking at what others had that she didn't and it made her very unhappy. She begged her husband for a new dress and he gave her his savings for it. She begged him for a piece of jewelry and he told her to borrow it, which she did. She felt she simply could not go to a ball like this one and not appear to be richer than she was. She was hoping that she could live the life of the wealthy for one night, which she did, and then she learned the hard way to appreciate what she had, or at least one would hope she did.