Fire is an absolute.
There is no way around it. Either death results – or life. No matter how one tries to twist that thought in their head, it can mean nothing else. Fire kills, consumes everything it touches. It isn't like the other benders' elements.
Air floats the spirit, bringing it closer to peace. Air does not destroy things without meaning to. An airbender does not accidentally burn his favorite toy, just received as a Fire Festival gift from his mother. An airbender does not literally get chained to a wall for a day and a night merely for forgetting one pose in a Dragon sequence and losing his control. An airbender does not go without dinner, again, for singing his nurse's hair. An airbender is peaceful, and lives just so; riding the breaths of the Earth herself.
Water calms the mind, sharpening the senses like ice. Water preserves, encases in the most ancient sense, and freezes in time. A waterbender does not bear a scar from his earliest experiments with the Fireblade technique. A waterbender does not earn the contempt of the class for being the son of the Emperor. A waterbender does not die in a duel as a matter of course. A waterbender is thoughtful, and maintains his poise; floating in the serene waters of thought.
Earth buries haste, forcing thought and consideration. Earth nurtures, helps a seed grow into beauty. An earthbender does not rush in, gaining a scar and a bitter lesson. An earthbender does not itch to feel the power rush through his veins once more, only once. An earthbender does not dream at night, alone and rabid, of the thrill of death, the horrible, insatiable thirst for more fuel. An earthbender is cautious and wise as the ponderous cycle of erosion.
Fire does not bring peace. Fire eliminates thought. Fire does not stop, moving onward and onward until something, anything, stops its progress. Fire kills everything, burning and destroying until there's nothing left, of its fuel or the bender that once thought he controlled it.
Fire is an absolute, causing only death. One day, I, Zuko, banished prince of the Fire nation, will fall to it as well. There is no way around it. It is a lesson that every firebender learns. No one uses fire without first accepting their own death.
I pray now, to the god or goddess or anyone, do not let me die like this! I am too young: to lead; to master my element; to control myself. I cannot stop the fire in my soul from possessing me, every single time, without fail, that I even call a candle's flame to me. I am not ready to die like this, a victim of the fire I sought to direct and bend to my will.
I am not ready.