The thing about zutara is that from a writing perspective, something happens that is, I think, coincidental but only enhances them as parallels, and that's "pair the spares" syndrome.
Zuko is never the main villain. Katara is never the main character. People have pointed out that they always end up together in the finale of each season. The main villain of season one is Zhao, so what is Katara going to do? She fights Zuko. The main villain of season two is Azula, so what will Katara do? Bond with and experience heart-breaking betrayal from Zuko. Aang fights Ozai in the finale, so what should Katara do? You guessed it, she's helping Zuko fight Azula!
The fact that you can actually trace a developing narrative following both characters' growth revolving around each other is also crazy.















