Madame Loisel was a woman who desired to go to parties, to have a lot of fancy dresses, and to move in rich social circles. She expressed this desire to her husband often, and was discontented and unsatisfied with her current life that was devoid of any luxuries and fine social events. So, when her husband brings home an invitation to a super fancy dinner party and dance, one would expect her reaction to be one of happiness and joy. Instead, ironically, she is upset. The text states,
"Instead of being delighted, as her husband had hoped, she threw the invitation on the table crossly, muttering: 'What do you wish me to do with that?'"
Her husband is astonished--he can't believe that she isn't excited about this invitation to an event like she has craved for years. She goes on to explain that she has no dress to wear to such an event--is she supposed to go dressed like a pauper? And, she has no jewels or pretty things to adorn herself with. So, the invitation just upsets her, because it is useless without the propoer party gear to wear. She refuses to show up in any of her dresses. It's not a very grateful reaction, but, gratefulness is not Madam Loisel's strongpoint.
Her husband sacrifices money to get a dress, and she borrows a necklace from a friend, and it is only after these things occur that she is finally happy and excited about the invite. But her initial reaction was one of dismay and unhappiness. I hope that those thoughts helped; good luck!