The importance of first impressions is a central theme in Jane Austen’s novel. Some of the characters’ first impressions prove sound, but for the most part, the initial glimpse of another character proves misleading. We can contrast Jane Bennet and Charles Bingley, who are quickly taken with one another, to Elizabeth Bennet and Fitzwilliam Darcy, whose misunderstanding is almost total. Although Jane and Bingley are driven apart, it is not because they were wrong about each other. Rather, they are constitutionally similar in that both are trusting, open, sincere people. Both Bingley's sister Caroline and his best friend, Darcy, have suspicious natures and cannot believe that the other two are perfect complements to each other.

Considering Lizzie and Darcy, Lizzie forms a negative impression of him because he is not socially skilled, which she assumes means he is an arrogant snob. His initial impression of her, aside from her mockery while they dance, is largely based in her other family members’ inappropriate behavior. Although it takes a while for them to get past those biases, ultimately they develop a strong friendship that will be a solid basis for their marriage.

In addition, almost everyone falls under Mr. Wickham’s spell in initially seeing him as a forthcoming, reputable young man. We learn that part of the reason Darcy became so suspicious about young people’s intentions is that his trusting manner had left his own sister open to this predator. To drive home her point about first impressions, Austen makes the reader the subject of her little deception. The reader is led to believe, as Lizzie does, that Darcy is arrogant and cynical by nature: we join Lizzie in erroneously jumping to a negative first impression.

The very title of the book itself is concerned with the theme of first impressions. Elizabeth Bennet's first impression of Mr. Darcy is that of a cold, aloof man: someone she wouldn't want to know in a million years, let alone dream of marrying. In short, she's prejudiced towards him. Mr. Darcy, for his part, sees Lizzie as a pretty but ultimately unsuitable young woman from a family of vulgarians far beneath him on the social ladder. As well as prejudice, therefore, he has considerable pride, or arrogance.

Later on in the story, Lizzie will have her first impressions of Darcy confirmed by the devious Mr. Wickham, who proceeds to spin her a shaggy-dog story about Darcy that paints him in a very bad light. There's not a word of truth about what Wickham says, but Lizzie's ready to believe his story for two reasons. First, because it corresponds to what she already thinks of Darcy. And second, because Mr. Wickham appears to be such a thoroughly decent chap that she has no reason to doubt his word. Lizzie's flighty young sister Lydia will also be mistaken in her first impressions of the superficially dashing but caddish Mr. Wickham, eloping with him and causing quite a scandal in the process.

In Pride and Prejudice, one important theme is about the dangers of first impressions. In fact, Austen originally titled her novel First Impressions. Because Elizabeth and Darcy both have distasteful first impressions of each other, they begin with animosity between the two. When Darcy is not impressed with Elizabeth at first, he makes insulting comments about her. Elizabeth overhears and immediately judges Darcy as rude and arrogant. Truly, Elizabeth and Darcy begin to dislike one another from the very beginning:

The first contact between Darcy and Elizabeth is made at the ball when Bingley asks Darcy to dance with her. Darcy’s superiority rings through when he remarks that Lizzy is not handsome enough for him. Bingley states that all the girls are handsome. Darcy insists that only Jane is beautiful.

After hearing Darcy's insulting comment, Elizabeth begins to hold a grudge against the competent, wealthy Darcy. Truly, Elizabeth and Darcy are filled with pride and prejudices from the start. Clearly, the two have begun with wrong first impressions. 

No doubt, Darcy is not attracted to Elizabeth in the beginning. In turn, Elizabeth is disgusted with Darcy's arrogance and insulting candor.

Later, Darcy becomes attracted to Elizabeth and proposes to her. Because of Darcy's prideful attitude, Elizabeth refuses to accept his proposal in marriage: 

'From the very beginning, from the first moment, I may almost say, of my acquaintance with you, your manners, impressing me with the fullest belief of your arrogance, your conceit, and your selfish disdain of the feelings of others, were such as to form the groundwork of disapprobation on which succeeding events have built so immovable a dislike; and I had not known you a month before I felt that you were the last man in the world whom I could ever be prevailed on to marry.'

Clearly, in the beginning, Elizabeth is not impressed with Darcy and his wealth. She has formed her own prejudices. She finds Darcy's arrogance distasteful. She rejects his proposal. In error, she believes Wickham's untruthful account of Darcy. Again, the theme of first impression is evident. Elizabeth perceives that Wickham is trustworthy. She is immediately drawn to him and his charming personality.

Again, Elizabeth judges wrongly. Austen masterfully creates a story which shows how first impressions can be misleading. Elizabeth falls for Wickham. Her first impression is favorable. She believes Wickham is a worthy man.

Throughout the novel, Austen proves how first impressions can be so wrong. In fact, Austen uses the complex concept of first impressions as one of the work's central themes. Elizabeth admits that her first impressions were off base:

It is only when Elizabeth herself admits that her first impressions were wrong, both in the case of Wickham and of Darcy (especially when she discovers the part he played in arranging Lydia’s marriage to Wickham and thus easing the disgrace somewhat), that she is able to discover her true self.

Amazingly, Elizabeth finds her true identity when she finds true love with Darcy by accepting all his flaws. The theme of the validity or error in first impressions is Austen's story. Elizabeth and Darcy marry and find true love despite first impressions:     

As the two converse after their engagement, both admit that their first impressions, though flawed, were not completely wrong. Only by accepting those flaws do Elizabeth and Darcy find happiness.