Back in Ch. 5, Elizabeth jokingly promised her mother that she would never dance with Mr. Darcy, and agrees with Charlotte that while Mr. Darcy may have a right to be proud, "I could easily forgive his pride, if he had not mortified mine."

This, too, is lighthearted in tone, and although she had earlier laughed off the "She is tolerable; but not handsome enough to tempt me" remark at the assembly by retelling it with "great spirit" to her friends and laughing it off as something ridiculous, it seems that she was more truly mortified by his dissmissive arrogance and his criticism of her than she lets on--even to herself.

All the behaviour at Netherfield is interesting, for Elizabeth is always examining it from the perspective that Mr.Darcy could not even be prevailed upon to dance with her, not even by his best friend, because she was not 'handsome enough'. She ought to be able to dismiss his remarks, but unfortunately, Mr. Darcy is not the only one who has not found her looks to measure up--there is also her mother.

Although the Bennet sisters are reputed to be beautiful (Bingley heard of this before he met any of them), Elizabeth also has heard all her life that Jane was 'the beauty'. Mrs. Bennet's remarks such as "I do not like to boast of my own child, but to be sure, Jane -- one does not often see anybody better looking. It is what everybody says" could not help but leave their mark on Elizabeth--no matter how silly her mother is. In a way, it's as though Mr. Darcy's comment confirmed what she'd been hearing all her life from her own mother.

So to me, at least, it's not surprising that she is taking all his remarks and his long looks at her as further proof of his initial negative assessment of her rather than as any sign that he might be having a change of heart. I think if a person believes that another person finds them unattractive, they are going to filter every look and remark from that second person through that perspective. They might see put-downs and slights where none were intended.

That's what Elizabeth is doing. 'He's looking at me because he disapproves of how I look.' 'He's speaking to me because he wants to put me down'. 'He's making it seem like he wants to ask me to dance because he really wants to look down his nose at me again for accepting to dance such a common dance' etc.