OMG AHHHH
Katara has always been there for Aang as a beacon of comfort in dark times. She's also very protective of him. Aang sees Katara through rose colored glasses because she's been a sort of wall for him to lean on, a home to go to for warmth, a pillar, but this is to the point where Aang outright dismisses any behavior that doesn't match his rose colored view.
Everytime Katara gets angry or anything of the sort he either isn't sure how to react or dismisses it entirely. He loves his rose tinted Katara... but he doesn't love Katara.
As well as the fact that Aang can always lean on Katara and vent to him... but you don't often see Katara venting to Aang. He's receiving most of the emotional support in the relationship. It's more like a mother-son relationship than anything.
I'm gonna be honest... I feel bad for Katara. She ended up with someone who doesn't see her for her. I can only hope that he stopped seeing her like that later on in their relationship...
And the episode... THE EPISODE. The Southern Raiders is an episode where Katara goes off to find the man who killed her mother and get her revenge. How does Aang react? By dismissing and invalidating her feelings and it's portrayed as some sort of wise guru stuff even though it's only making her feel like he doesn't understand her. That sounds like a healthy relationship, I'm sure.
You know who validated her emotions? You know who understood her and helped her? ZUKO.
At teh end of the episode- SHE LITERALLY GIVES AANG THE COLD SHOULDER AND GIVES FUCKING ZUKO A HUG
SHE WAS ANGRY AT HIM (Zuko) NOT LONG AGO BTW SO IMAGINE THAT
SHE JUST TREATED AANG, THE DUDE SHES SUPPOSEDLY IN LOVE WITH, COLDLY AND TURNED AROUND AND GAVE ZUKO, THE FIRE NATION PRINCE WHO SHE HATED A WHILE AGO, A HUG-
HOW IS KATAANG ENDGAME WHEN THIS IS HOW THINGS ARE GOING IN THEIR RELATIONSHIP FOR THE LAST HALF OF SEASON 3