Avatar: The Last Airbender, Book 3: Fire

Katara:
I think I understand why being a secret bothers you so much... you don't want people to think you failed.

Aang:
You're right, I don't. But the problem is, I did fail!

Katara:
Aang, that's not true!

Aang:
It is true! I was in Ba Sing Se, I was there! But I lost, and now the Earth Kingdom has fallen for good.

Katara:
It's not for good! Remember, there's still a plan: the invasion!

Aang:
(angrily) And I hate the invasion plan too! I don't want you or anyone else risking your lives to fix my mistakes! (calmer) I've always known that I would have to face the Firelord, but now I know I need to do it alone.

Katara:
Aang...

Aang:
(firmly) Katara, please...just go. Please.

Katara:
(turning to leave) Is there anything you need?

Aang:
I need to redeem myself. I need my honor back.