If you were a bender Avatar the Last Airbender, what element would you bend?

You totally need to go Air

@Roch2001 Air definitely does have its perks.

Except submerge the entire world in an endless war for no justifiable reason. No good reason at all really.

Surely "nothing" apart from that.

And that's how it started - the notion of a benign "little bit" of imperialism by Sozin as a way of supposedly spreading the benefits of their technologically advanced and prosperous civilization, of "sharing it with the rest of the world", and covering their country in glory in the process ends 100 years later in an attempt at burning everyone and everything different and not Fire Nation to ash in all directions and seeking to purify the world by fire. But usually the ideas which led to cyclical wars without end and tens of millions of people killed originated in our real world too in ostensibly altruistic noble impulses of striving to raise one's own people up and do right by the world, not setting out to do bad. And if anything, they're even more bloody and destructive as a result, when you convince whole societies you're fighting for something glorious.

But in the end, there is nothing glorious about what the Fire Nation was doing. If it wasn't physically stopped by force it would have eradicated all difference in the world and permanently and irrevocably wrecked the natural elemental balance, throwing man and nature into chaos.