"I remember hearing you once say, Mr. Darcy, that you hardly ever forgave, that your resentment once created was unappeasable. You are very cautious, I suppose, as to its being created."
"I am," said he, with a firm voice.
"And never allow yourself to be blinded by prejudice?"
"I hope not."
"It is particularly incumbent on those who never change their opinion, to be secure of judging properly at first."

– Jane Austen

Pride and Prejudice, Chapter 18. Elizabeth challenges Darcy on his being quick to judge and refusing to change his mind once he forms an impression about a person’s character. She questions if he is ever blinded by prejudice. She puts it him that those who never change their opinion have a responsibility to ensure that they form the correct judgment in the first place. She is referring to Wickham’s claim that he has been been mistreated by Darcy. But Elizabeth shows her prejudice by accepting Wickham’s word and making up her mind without hearing Darcy’s side. Her advice on hasty judgments is ironic, given that she is guilty of exactly that with Darcy. Her criticism of him shows her own lack of self-awareness, for she equally is quick to make up her mind about others and stubborn about changing it.