Mia stabbing Lana in the chest with an ice cream cone after Lana insults Tina. Doubles as one for the film.
Phillipe helping Helen and Mr. Gianini elope to Mexico and avoid the tawdry, expensive Shotgun Wedding that his mother Clarisse has arranged.
Mia ripping Lana's (fake, but she didn't know that) braid off for calling Perin a hermaphrodite.
Mia's speech when she runs for student body president.
Lana even later acknowledges it was an awesome speech, and in book 9 recommends Mia to speak to the Domina Rei. Mia kicks it out of the park with her speech about Princess Amelie, a sixteen-year old princess who ruled during the Black Plague, saved lives despite her uncle attempting to usurp the throne and burn her proclamations, and mandated that Genovia become a constitutional monarchy in her last proclamation.
Mia becoming a published novelist at the age of eighteen.
From the films:
From the second movie, after Viscount Mabrey has staged a humiliating accident while Mia was inspecting the royal guard and Joe has figured out he was behind it:
Joe: Viscount, you may not be aware of what my job entails as the Royal Head of Security. My job is to protect the crown. To make sure no harm comes to the crown. To step in when someone toys with the crown's emotions.