Darcy does treat Caroline rather snarkily at times but he never made a point of saying how unworthy of his regard she is either so she continues to have hope in him. I agree Darcy was pleasant mannered and teasing at times with Lizzy but his improved behavior and manners were not enough to convince her that his opinion had changed. That does not mean Lizzy hates Darcy; it means he has failed to make his new opinions known to her. Several folks have said Lizzy should have been less blind to his change; I do not agree. What I mean is, it is reasonable for Lizzy to believe Darcy considers her unworthy of attention as that is what he said. I am not sure why she should just forget his clearly stated opinion and look for signs of attraction without any encouragement from him. Lizzy is partial, she misinterprets his intentions at times but she has good reason and I do not blame her for it.