This is based on opinion. Please don't list it on a work's trope example list.
Tear Jerker / How I Became Yours
When Ursa comes to visit Azula. Back this up a bit...Azula has long been under the impression that her mother thought she was a monster. She has thus craved Ursa's approval since she was a child, but she doesn't think she will get it, since she believes Zuko is Ursa's favorite. So, present day, Ursa comes to visit, and what does she do? She coos over Zuko first, comforting him about his scars that are supposed to be old news. And then she turns to Azula, and says that she always loved her, even given "What she used to be." This isn't a heartwarming scene about a mother's reuniting with her child. This is a scene in which a mother says, "Oh, thank God, you're finally different." No wonder Azula's crying. I was.