Easily my favorite episode of the series was Katara confronting the murderer of her father, Yon Rha. The usually composed Katara reveals her deep seeded vulnerabilities. She had to confront the monster that has been festering inside her since the day of the attack, which emboldened her to become the very best Water Bender she could be to make up for all the others lost. Most stories would attempt to humanize the person whom the vengeance is directed to in order sell its futility. But instead, Yon Rha is depicted even less sympathetic. Perhaps even pitiable.
But the importance wasn't on Katara trying to find a middle ground with Yon Rha, it was her conquering her demons head on. In the end, she wasn't a murderer. That isn't who she is. When she became a Water Bending master, it wasn't so that she could kill the dreck, it's so that she could protect what she still had. Her friends and family still with her. On the opposite aisle, you had Yon Rha who was quick to exchange someone he should've cared for just for the chance to preserve himself.