The external conflict that was proven unnecessary by the end of the story involved the Loisels' distress over the loss of the borrowed necklace, their effort to replace it, their borrowing money for the replacement and then struggling for ten years to repay the borrowed money, and finally Mathilde Loisel's finding out from her friend that the lost necklace had been a fake.
Madame Forestier, deeply moved, took her hands.
"Oh, my poor Mathilde! Why, my necklace was paste! It was worth at most only five hundred francs!"
Madame Loisel's internal conflict involved her dissatisfaction with her humble station in life and her dreams of having a luxurious lifestyle and upper-class social status.
She had no gowns, no jewels, nothing. And she loved nothing but that. She felt made for that. She would have liked so much to please, to be envied, to be charming, to be sought after.
A change in Mathilde Loisel's attitude could have prevented her internal conflict. It took a catastrophe, however, to change her attitude. Once she had lost the borrowed necklace, she became much more realistic, much more down-to-earth. She had to work all day long and couldn't afford to lie back and daydream. She lost her beauty early and lost her fantasies along the way.
Many readers have expressed the opinion that Madame Loisel got just what she deserved. She should have been satisfied with her humble station in life. But she was not really so much different from most of us, especially when we are young. Mathilde's creator Guy de Maupassant was a great admirer of Arthur Schopenhauer. Here is a pertinent quote from Schopenhauer, the pessimistic German philosopher:
Of course, as Schiller says, we are all born in Arcadia; in other words, we come into the world full of claims to happiness and pleasure and cherish the foolish hope of making them good.