Soren reuniting with his family at the end. Especially how much his family was so proud of him.
In a weird sort of way, Kludd and Nyra's interactions. Nyra is clearly impressed with him and has multiple "So Proud of You" moments, all of which seem to be genuine. When Kludd makes the decision to stay in St. Aegilious, it occurs when Grimble has Nyra pinned down and Kludd resolves to stay after seeing her give him an almost pleading look, implying that he's staying because he wants to be with her.
Another great example is when Soren and his friends are all officially made Guardians of Ga'Hoole. Soren's parents could not be prouder, and later, Soren is recounting the tale to some owlets, just like his father did to him. And like Ezylryb, Soren is now a heroic idol to youngsters.
Soren: Da! The stories... they're real! Noctus: You made them real, Soren.
— Legends of the Guardians: The Owls of Ga'Hoole, at the end.