Their mom is awful and selfish. They deserved better. She caused inferiority complexes between Azula and Zuko. Azula wanting her mother's affection and love since she always thought Zuko was only loved. And Zuko being unable to be a proper older brother to guide his sister when their mom abandoned them. That's what she did. Abandoned them. He was so caught up in his inferiority complex towards Azula. It's just an unfortunate situation she caused by selfishly choosing to forget them and abandon them.
well I guess as long as I found out where the mother is the story has ended for me, time to move on Azula, no just kidding, It hurts, but your evil so its good. jk