Thought I'd do regency, for a switch. It wasn't a good choice of books, though...
Harriet is a brat. She is an orphan who was raised by a school, but because she has scads of money, she has always been the little diva, and her pranks and mischief was tolerated. Over the years her behavior gets more and more out of hand, until she makes up a guardian who 'writes' to her, that she shows off to the other girls.
Then the guy actually shows up. And Harriet sees him as her way out of the school, and begs him to help her, then throws a tantrum, and then stows away in his carriage. From there on out, if there's a bad decision to make, Harriet makes it, and keeps the poor man busy rescuing her from her own idiocy.
I hated Harriet. I hated him for falling for her. It was terrible.