I can't remember how old I was when Avatar: The Last Airbender first came out, but I remember I was in some sort of phase where I thought I was too cool for cartoons. HA! I saw Avatar advertised somewhere, and thought, "This is for babies. Hard pass."
Maybe it's a blessing that I finally gave it a try when I was 29... My staff wanted to do an "Avatar and Masculinity" program at my work, and I was fascinated by what they had to say about the show. When I sat down to watch it for the first time... man, I had been missing out! There's so much depth to the Avatar universe. So many layers that make the show enjoyable for both kids and adults alike. It's fantastic.
And well, I love me a troubled, complicated villain. Or perhaps an antihero. I'm not sure what you'd call Prince Zuko by the end of the show, but he IS troubled and complicated. He has layers, and that makes for great character development and a great story.
I hope we get more from this universe soon!