The reason behind the outrage caused by Kate Chopin's novel The Awakening may very well lie on the fact that Chopin breaks with every social rule of decorum as they were considered in the late 19th century Creole South. These rules include that the female role is to be that of wife and mother, that women should abstain themselves from self-satisfaction, that women should relinquish their role as secondary to the husband, and that sex is not to be explored beyond its role as the act of procreation.
Undoubtedly, Edna Pontellier's awakening leads her to question all of these senseless rules. First, she questions whether she even loves her husband. In his dull and loveless treatment of her, she wonders if marriage and love are even connected.
Second, she realizes that her maternal instinct is quite low. She never once thought of having children except when she got married. Therefore, she had children as a task, and not as a wish. When she seems to lack the skills to be a nurturer and a nurse to her children, she begins to wonder what is the point of it, anyway. That certainly could have caused a scandal back in the day.
The fact that Edna acknowledges her love for Robert to herself, and accepts wholeheartedly that she would not mind engaging in a relationship with him is also a source for prudish shock. Imagine a woman who admits to loving someone other than her husband, and who cares very little about admitting it. Moreover, the fact that Edna happily allows her husband and children go somewhere else so that she can physically move out of her house into the "pigeon hole" is outrageous in the eyes of the women of her time.
Yet, it is the fact that Edna simply turns into someone completely different is what may have created the grudge among her social peers; women were just barely beginning to discover their independent needs in the early 1800's. As with every social change, these discoveries first stormed society, and then transformed it. Chopin was quite ahead of her time in creating a character that takes complete control of herself, and her life.
The last shocking event that surely sent society in a fury is the fact that, after discovering all these things, Edna chooses to commit suicide. A mortal sin declared by the Catholic Church, Edna may have been misinterpreted as submitting herself entirely to some evil ceremony. However, the modern reader can certainly understand that Edna simply intended to liberate herself from an oppressing world that points at her discoveries and calls them "sins". Her final choice is a submission, indeed, but one which sends her back to nature. Perhaps, she wishes to be reborn..who knows if in another time and place where she could have expressed her true self.