D'Artagnan promising the people of France to take up the complaint of Rotten Food to the king personally. Bonus points for having the guts to eat a Tomato to determine whether or not it was spoiled.
Athos practically gushing with pride for his son.
Phillipe meeting his mother for the first time.
Athos taking on the role almost of a surrogate father to Phillipe. While some like Aramis consider this relationship merely as Athos looking for a replacement for his late son, it is more than that; Athos sees Phillipe as a real person, is genuinely concerned about his happiness and wellbeing, and has deep misgivings about what they plan to do, knowing that they are essentially forcing Phillipe to risk his life for their ambitions.
Aramis: Do you think I've not considered everything?!
Athos: Have you considered it is not only our lives you risk, it is also Phillipe's?