Why was mrs loisels anxious to hurry away from the ball?

Madam Loisel did not want people to see that she had wraps common to poor people instead of having fur wraps to match the illusion that she was rich,

the wraps he had brought, the modest wraps of common life, the poverty of which contrasted with the elegance of the ball dress. She felt this and wished to escape so as not to be remarked by the other women, who were enveloping themselves in costly furs.