It is safe to say that Caroline Bingley is one of the most hated of Austen's characters. While she certainly has other, more serious, faults, much of the hatred seems to come from general disapproval of her continued pursuit of Mr. Darcy, probably because many of us feel a kinship to Elizabeth Bennet. This post looks at why Miss Bingley's pursuit makes sense.
At the beginning of Pride and Prejudice, Caroline Bingley is presented as the fashionable unmarried sister of the wealthy and eligible Charles Bingley who will be acting her brother's housekeeper while he is at Netherfield. On its face this sounds like a good situation, and it is except for the fact that she will lose that position the second her brother marries. After her brother's marriage she will go from being in a position where she performs a useful function that gives her a degree of status to a position where she is a mere dependent who lives in her brother's house without any real authority over anything.
Enter Mr. Darcy, wealthy, handsome, intelligent, educated, wealthy, independent and all together an excellent example of a good Regency catch. If anything Miss Bingley's interest in him is a sign that she has good taste in at least one respect and rationally speaking, Miss Bingley isn't a horrible match for him. She herself is apparently educated, even if not a great reader, she associates with people of rank, and has a respectable fortune. She and Darcy appear to have a relationship (not in the romantic sense) based on the mutual enjoyment of snobby repartee while in Meryton.