Strong story line with great character development. You can tell makers have given everything they can offer.

Animation is very beautiful and look great when bending has performed.

Also love how supporting characters have given important place in the story, they didn't just make Avatar did all the work.

Also show have a very good writer team.

Meaningful message with a lot of dialogues specially from uncle Iroh.

Can't believe a show which can be loved by Anime and cartoon lovers together.

Another great thing about this show is perfect ending, no guilt that something is missing.

Ofcourse except what happened to Zuko's mother (you can the comics to know what actually happened).