Education

The fire nation education system brainwashes the children to think that their nation is the best. They are not allowed to have any form of self-expression, including dancing, but they all hold individual identities inside of them. They start off the day by reciting the Fire Nation oath:
"My life I give to my country. With my hands I fight for Lord Ozai and our forefathers before him. With my mind I seek ways to better my country. And with my feet may our March of Civilization continue."
Agni Kai

An Agni Kai is the traditional method of resolving an argument between two firebenders. It begins with the two duelers on to opposite sides of a specified area, kneeling and facing away from each other. Then they stand up, face each other, and take off their shirt-things, leaving them shirtless. They begin fighting, using any means they can to disable the combatant. The fight is over when one dueler burns the other. In the TV show, Zuko is present for all three Agni Kais mentioned, but he doesn't win all of them. ): Boohoo Zuko, better luck next time.
Sozin's Comet

Sozin's comet passes by the planet every hundred years, which signaled the beginning and end of the Hundred Year War. Because it passes so close to the planet, firebenders can draw energy from the heat, and their firebending abilities will double, and they can make actually fire by manipulating their chi. THe power of the comet enabled the fire nation to completely wipe out the air nomads, demonstrating its enormous power.