Nightmares and daydreams
Toph and Zuko had similar nightmares.
Being alone, being a failure, being trapped by parents who would and could never understand them.
Trapped in gilded cages that seemed to suffocate them more and more each day. Realizing that they were born helpless and that they would never live up to being heroes and warriors.
Both of them had woken up at night, drenched in sweat and pinching themselves to make sure that they were awake, where the nightmares couldn't hurt them.
Now that the war was over, the nightmares had become real. And both of them had conquered them.
Zuko had conquered his father's evil and had proven himself worthy of the throne and the love of his people. Although he had been bruised and battered by the fight, he had emerged triumphant. He had emerged Fire Lord.
Toph had proved herself a true warrior. She had fought for her nation and her family and had won great respect. When she returned, a General of the Earth Nation army, her parents had been forced to realize their little girl wasn't so helpless.
Back to back, they had fought together to build a world where they would only have pleasant daydreams of a better future.