These are what we call the 'YMMV items.' Things that some people find in this work. We call them 'your mileage might vary' because not everyone sees these things in the same way. This starts discussions in the trope lists, a thing we don't want. Please use the discussion page if you'd like to discuss any of these items.
Moral Event Horizon: Zuko's whole attitude toward Aang understandably changes after the Siege of the North and the massive slaughter that someone he trusted and let walk free has inflicted on his countrymen. They've patched it up a bit, but Aang and Blue are still very definitely not friends anymore. To be fair to Aang, the Avatar Spirit/Raava did it; and to be fair to Zuko, he doesn't know that.