Let's look into the first activities that Nora is conducting when the play opens. She is out shopping, getting a Christmas tree, eating macaroons behind her husband's back, playing with her children, and responding to her husband's terms of endearment, which include "little squirrel," and a "lark." He warmly scolds her for eating sweets, criticizes her spending habits, and basically demonstrates with his behavior that he is the proverbial "head of the woman," a paradigm that Victorians lived by. 

But I want you to realize that the head of every man is Christ, and the head of the woman is man, and the head of Christ is God.(1:Corinthians 11:3)

Judging by the way Nora responds to these dynamics, we can safely assume that she is content with her position; that she was groomed to be her husband's wife and her children's mother. 

Towards the middle of the play, Nora's behavior does not change, but her mindset begins to show signs of self-doubt and doubts about her husband. She talks about a "miracle" that would happen and make everything go away. This "miracle" she refers to is the scenario that she hopes to see if her husband ever finds out about the deal with Krogstad. In this scenario, Torvald would understand Nora's sacrifice, appreciate her for it, and then take the blame for her to protect her honor. Nora was torn, because part of her believed this would be possible, and another part of her knew it wouldn't happen.

Helmer [walking about the room]. What a horrible awakening! All these eight years--she who was my joy and pride--a hypocrite, a liar--worse, worse--a criminal! The unutterable ugliness of it all!--For shame! [...]No religion, no morality, no sense of duty-[...]and this is how you repay me.

Nora's "miracle" does not occur. As such, Nora is left disillusioned, frustrated and, to a point, devastated. Who is this man she married? How can the man for whom she has sacrificed so much call her such awful names, and make the horrible suggestions he makes? She has finally seen his true colors, and this is when she realizes that all her life has been a farce. She has lived like the plaything of a very shallow man. Knowing all of this was enough to make Nora decide on the spot that it is time for her to go. She realizes that she has never been happy and she goes away, leaving her husband and children behind. 

When the play opens, Nora appears to be a docile, submissive wife who takes great pleasure in proving a warm and inviting home for her family. In fact, in the opening scene, she is “humming” as she prepares the home for a delightful Christmas experiences. She seems to be a young wife who is eager to please her family in all things. She even allows her husband to dictate her budget and her diet, hiding the “macaroons” when he enters so that he will neither realize that she bought them nor that she is eating them. However, these outward indications of a passive and unassuming character are misleading.

As the play progresses, Nora takes several actions that indicate a more calculating nature. She promises Mrs. Linde that she would ask her husband to help her find employment. She says that she will “broach the subject very cleverly.” She obviously knows how to manipulate her husband. In addition, she borrowed money from Krogstad through the use of forgery. She is clearly not a simplistic “squirrel” who possesses no thinking ability. Rather, she is a woman capable of using both reason and deception to accomplish her goals.

The difference in Nora’s personality, therefore, concerns her perspective. From the earliest days of her marriage, she treasured her husband, Torvald, even to the point of risking her freedom for him. She was completely aware that her fraudulent act might result in legal punishment.  Still, she takes the risk because she loves him and she believes that he loves her. She is dedicated to her marriage and demonstrates that dedication through action. She accepts her husband’s dictatorial manner and belittling remarks for the sake of the marriage. Moreover, she discreetly conceals the fact that he owes her his very life.   

Following his discovery of her misdeed and despite the fact that she committed the crime to save his life, Torvald rejects Nora. He berates and insults her, refusing to show her any mercy. He disparages her character and threatens to take her children from her. He offers no words of appreciation for her efforts to maintain a happy marriage and a happy home. Then, he receives the note from Krogstad that relinquishes the threat of legal action. Immediately, he rescinds his hurtful words, reassuring her: “I have forgiven you, Nora; I swear to you I have forgiven you.”

Nora refuses to accept these empty words from her husband. His former comments have ruined her perceptions of their marriage. He has destroyed her belief in the power of their love and she is now fully conscious of how little he thinks of her. She knows that he does not truly respect or value her. This knowledge emboldens her and she refuses to remain in sham marriage, where she is treated like a lifeless, unfeeling doll. She is disillusioned by the reality that her marriage is a farce.