The early days of Aang and Zuko's friendship makes me feel so soft inside.
Imagine that after years of strife, suddenly you have this new friend who just wants to make you laugh and smile, because that's what is fun for him. It's the polar opposite of what your life has been for years, and it's confusing, but you can admit that it feels good. You're slowly getting the hang of having friends and being a pleasant person to be around. And best of all, your new friend forgives you! After years and years, your father barely forgave you for something you did that was actually the right thing, meanwhile what you did to your friend was objectively wrong, and he still forgave you within days after you'd proven that you were sorry. Your friend is patient with you, and it feels like you did nothing to earn this, but he reassures you that this is normal. This is the way you should be treated.
Imagine that you finally are able to gain a piece of your old life through your new friend, who you'd wanted that from for months now. You finally are learning who he actually is and you come to find that he is much different than how you originally imagined, for the better. He does the right thing. He is stubborn, but not so much that he can be reasoned with. He is smart, funny, insightful, and most surprising of all...terribly awkward. And he's sorry. He found the right path and he did it on his own, without the need to convince you. He wants to make things right, to help you learn firebending, and to fix what he and his forefather did in any way he can. He is servile in a way that is uncomfortable at times, but he is learning how to function heathily. You see his pain and you understand why he did the things he did, although that doesn't make it right, and you help him realize that it was wrong.
And most importantly, you both plan to rebuild the world together, hand in hand .