"Sue" is a sublimation of the desire "that everything should be". In the case of the kidney, this is the desire for child independence: Peppi is physically strong enough to drag a horse and storm two adult bandits, she lives alone, but cautiously supplied by a far-floating daddy with a gold box for all needs and a house-villa. That is, the world of boring forcing to go to school, being polite and disciplined adults - over it has no power. She knows geography well (when swimming with her father, the little girl came out), but at the same time she does not want and does not teach elementary reading and writing skills.