WARNING ------- SPOILERS AHEAD
Probably the greatest animated show in the world, and if not, it's definitely up there. This show is just... just perfect, in my opinion. Every season and episode has it's own beauty, and this show even gets out messages in it's own metaphors, and doesn't hold back on the horrors of war. Excellent character development. One of the reasons people MIGHT not like the season finale is because they think that the whole energy bending / lion turtle stuff came out of nowhere, but if you watch closely, you realize they actually do have a bit of a setup in season 2. I'm not going to tell you, that's for you to find out :)
I can barely think of a single thing wrong with this show. I'm seeing several hate comments saying that "the comedy doesn't mix well" and "bald kid with tattoos on head is boring". A, that's just judging a book by it's cover and insensitive to bald people and B, the comedy mixes perfectly, like everything. My praise is not exaggerated. The characters are so compelling, they've done a great job with the worldbuilding, and the fight scenes and choreography is also great. The different bending styles are so great. Overall, amazing showw!!!