It's not that the princess's situation isn't pitiable, it is, but it's her attitude that's really annoying. She's come down with serious case of "woe is me" syndrome. Moreover, while we all have moments where we pity ourselves, the way she disrespects her mother and chooses to be ignorant of other people's struggles is what really irritates me. As the MC pointed out, she has no idea about the struggles outside her sheltered life. Plus it's kind of messed up to sack your "friend" (as real friends wouldn't do this) with a marriage that you find so repulsive you'd rather die than have, and if it's ever found out you switched everyone associated gets murdered.