I liked Yue. She had an interesting voice.
I find Katara annoying sometimes, Toph too, but only occasionally. I like serious Aang, and goofy Aang when he's actually funny. I didn't like his screaming and meekness in the Firebending Masters.
All the characters are marvellously flawed. It's what makes them so interesting. It can also cause people to dislike them.