"The Self-Improvement of Salvadore Ross" is an old Twilight Zone episode where a man realizes he can trade traits and conditions with other people, and begins to improve himself in order woo a woman. Unfortunately, he makes the mistake of trading her father for his compassion (since she only wants to marry a man as loving and caring as her father), and things go rather poorly for him when he tries to ask her father for her hand in marriage...
I guess I'm looking for trait swap stories where the traders have to be willing, the protagonist is slowly improving themselves in order to accomplish something, and then they make a trade that causes things to go south. (Bonus points if they include career downgrades, IQ loss, etc.) Are there any stories like that?