Madam Mathilde Loisel has a very classist outlook of society. She has always considered that she is an aristocratic woman that was born into a modest family due to an “accident of fate”.
When her husband, who is a modest clerk who works in the government is able to get an invitation attend a ball of the Ministry of Education, she is horrified because she does not have anything elegant and expensive enough to wear. She definitely wants to go but her first reaction is actually worrying about what higher class people will think about her.