Okay, so, I'm bringing up a topic that many people rag on Katara for, but I see it differently. As you can probably already tell from the title I'm giving an explanation as to why Katara was always talking about her mother. It's a lot darker than just having a really strong mother-daughter connection, and it's much more depressing to think about.
Katara constantly brought up her mother dying and how much it scarred and traumatized her and her and the fandom just thinks that she's just a huge crybaby who can't get over the loss of her mother, but there's SO more that they don't think about. When we see the flashbacks of Katara in the igloo with her mother the firebender there, he was very clearly unarmed meaning he most likely used Firebending to kill her (It's also very explicitly said if not hinted in the show what happened) Katara knows this too. I mean, how could she forget? She would have obviously taken notice of this, ya know, based on what she saw when she went back to the igloo where her mother was. This is confirmed as, after she got her dad to come back to the igloo with her, they both went inside to see what had happened.
Both of them. Right here
This scene was set almost immediately after her mother had died, and most likely right after the firebender had already left the igloo he killed her in (if not, then there proly woulda been another dead body when dad got there (。_ 。)even more trauma). Remember, the firebender was unarmed and killed her with fire. Katara, when she ran in, had to see her mother's charred, dead, smoking body (or what was left of it). And people expect her not to try and talk about it? This is at least 10x more horrible then these people probably expected it to be and they don't realize what she really went through. Of course, Aang still lost his nation and Sokka had the same mother, but neither of them had to see the burning, bloody remains of either those splattered on the floor of their home. That is MEGA DEPRESSING. Now, if you'll excuse me, I'm going to go get some ice cream and try to convince myself that I don't have problems.