An: Well, I was re-watching Bitter Work, and I found myself paying special attention to Iroh teaching Zuko about the elements, and bam. Story idea. Enjoy!
Disclaimer: If I owned ATLA, well the world as we know it would be quite different.
Toph Called it Love
His uncle said that by observing Water Benders, he had created his own Fire Bending move, and so, Zuko decided, he would better his own fire bending with the same tactic. Observation. And luckily, much to Zuko's own delight, he had the perfect specimen of a Water Bender to watch. For hours, Zuko would sit on the riverbank and watch her and the Avatar practice their bending in the waist deep water. Under any other circumstance, Zuko would have kept his eyes solely on the Avatar, but Zuko found he was much more enchanted watching Katara. Her graceful movements guiding the water around her body and then shooting it back toward the Avatar fascinated him.
Of course, this was the only thing about the girl Zuko liked. She wasn't pretty, nothing like the fire nation beauties he remembered from home. She was rough, dark skinned, and kept her hair back in a plain braid. She had a bad temper that rivaled his sisters, and she refused to speak to Zuko except in short snaps and enraged flares. Zuko returned her hateful words and temper tantrums readily. Every meal the group ate together was accented by at least two colorful spats between the two. He called it observing Water Bender limits.
Toph called it flirting and told them to stop.
However, in the water, Katara seemed completely changed. She was relaxed and gentle, teasing the water with her fingertips to come and play. She liked to laugh in the water, liked to play, liked to forget she was in charge of the world's most powerful child and act like the girl of fourteen she was supposed to be. Zuko couldn't take his eyes off of her. He called it observing Water Bender techniques.
Toph called it peeping and told him to stop.
At night, after a fight over how well the food was cooked, and then a another one over who would do the dishes, (Zuko because he never did anything, or Katara since she had made a terrible dinner and clean up after herself) The group of friends would retire to their respective sleeping bags around the fire. Unlike the other three in their party, Zuko and Katara never went to sleep right away. Katara chose to stay up and study her newly acquired scrolls or read a book she had picked up during their last stop in a city. Zuko chose to watch her discretely from across the fire. He was amused with the way her brow would furrow when she read something interesting, or the way she would sometimes lay her scroll on the ground and attempt to act the water bending motion out while remaining in her sleeping bag. Zuko called it observing Water Bender studying.
Toph sleepily called it obsession and told him to go admit his feelings.
Sometimes in the evenings, after dinner and before their second fight, Katara would grudgingly grab the dishes and head down to the stream with Zuko in tow still cursing her. When they would reach the bank, out of earshot of their friends, they would stop bickering and Zuko would whisper a quiet 'hello' and Katara would blush and reply in the same fashion. They would set about cleaning the dishes together and at some point, Zuko would lean over and kiss her. Katara would pause, kiss him back, and then finish the dishes. Zuko called it observing Water Bender relationships.
Toph called it love.