Avatar: The Last Airbender, Season 3

Zuko:
Listen everybody; I've got some pretty bad news. I've lost my stuff.

Toph:
Don't look at me. I didn't touch your stuff.

Zuko:
I'm talking about my firebending. It's gone.

Katara:
[laughs] I'm sorry. I'm just laughing at the irony. You know... how it would have been nice for us if you lost your firebending a long time ago?

Zuko:
Well it's not lost. It's just weaker for some reason.

Katara:
Maybe you're just not as good as you think you are.

Toph:
Ouch.

Zuko:
...I bet it's because I changed sides.

Katara:
That's ridiculous.

Aang:
I don't know. Maybe it isn't. Maybe your firebending comes from rage, and you just don't have enough anger to fuel it the way you used to.

Sokka:
So, all we need to do is make Zuko angry... easy enough.

[he proceeds to nudge Zuko in the waist and head with the hilt of his sword several times]

Zuko:
OKAY! CUT IT OUT! Look... even if you're right, I don't want to rely on hate and anger anymore. There has to be another way.