Answer:
Madame Loisel's internal conflict. Her dissatisfaction with her station in life and her desire to be rich propels the events of the story.
Explanation:
Madame Loisel was not satisfied with her lifestyle. She wanted more servants and most especially she wants to attend balls and frolic around with people that are above her station.
When her husband received an invitation to a party, she was determined to step out in grand style even though she couldn't afford it. This led her to Madame Forrester (I hope I got the name right. It's been a while since I read the text). She ended up spending the little her husband had saved and led the family to penury because of the necklace she had to replace which happened to be a paste, an imitation.
Cut your coat according to your size
