Mai on... Katoph!
"Many epic friendships were forged during the saga of Avatar: The Last Airbender, but the most tumultuous was the snippy relationship between Katara and Toph Bei Fong.
"Katara grew up in the South Pole with her parents and a OH SO HOT older brother but early on her mommy died THE INCIDENT CAN BE SUMMED UP WITH THE WORD 'BACON' and she was left as the only one who could take care of her woefully inept male relatives BECAUSE WE ALL KNOW THE GUYS WOULD BE LOST WITHOUT US thus she developed a habit of mothering anything smaller, dumber, louder, sadder, or dirtier than herself ALTHOUGH SHE MADE AN EXCPETION FOR FELLOW HALF-ORPHANS BECAUSE THAT WAS A TURN-ON FOR HER and ran with it as her own personal identity. This habit was only encouraged when she thawed out the Avatar and was recruited to follow him around picking up after him and cooking for him and bathing him and tucking him under his Bison's tail every night AWW SO CUTE I'M KIDDING I'M GOING TO VOMIT and further exacerbated by her brother who seemed to regress in maturity PERSONALITY-WISE NOT BODY-WISE as time passed on the road.
"Toph was a much more independently-minded girl who was raised by the world's most overprotective parents ever NOT THAT THERE'S MUCH COMPETITION THESE DAYS and kept a secret from everyone and anyone. Toph literally was forbidden from leaving her house and no one knew that her family even had any kids THEY DIDN'T EVEN CLAIM HER FOR TAX PURPOSES because they thought the fact that she was blind and shorter than a midget lemur made her as fragile as Ty Lee's attention span. As can be expected of anyone with even the most underdeveloped backbone Toph rebelled against this as much as she could which at first consisted of running away and later involved fighting in a professional wrestling circuit I THINK THAT SHOULD GET THE 'NON-SEQUITAR OF THE YEAR AWARD' and then finally culminated in running away with the Avatar to teach him Earthbending and committing random acts of terrorism and grand larceny when there was a little free time.
"As expected it didn't take Katara and Toph long to come to conflict because Katara quickly set about integrating Toph into their little family by assigning her chores and then shouting when they didn't get done THAT'S HOW ZUKO'S RELATIONSHIP WITH HIS FATHER STARTED GOING SOUR during which Katara demonstrated why 14-year-olds are not considered to be great parenting material by lowering herself to making fun of Toph's disability I FIND IT MUCH MORE EFFECTIVE TO INSULT HER LACK OF FEMININITY and nearly coming to blows AGAIN I'M REMINDED HOW OZAI'S DISCIPLINARY METHODS. Toph fully displaced her parental issues with her parents onto Katara when she rang away from the Waterbender and returned only so that she could keep crossing Katara by undermining her and hitting on her boyfriend IN TOPH'S CASE THAT DESCRIPTION IS BOTH LITERAL AND A EUPHAMISM and basically being as much of a brat as she never dared with her parents because then they would cut off her allowance.
"Toph and Katara continued their dreadful cycle of fighting and reconciling AND MUDFIGHTING WHILE THE BOYS WATCHED when Toph began running scams in various Fire Nation towns JUST IN CASE THEY COULDN'T ASSASSINATE OUR LORD THEY WERE GOING TO RUIN OUR ECONOMY and thus drawing attention to what was supposed to be a stealthy infiltration of enemy territory. Toph finally called Katara out on her tendency to act like the group's parental figure which Katara didn't like at all because if Aang thought of her as a mother then he was very unlikely to want to help her sort out her CONFUSED feelings for him AND IF HE DID CALL HER MOMMY AND ALSO WANT TO KISS HER THEN THAT WOULD JUST BE DISTURBING so Katara executed a full turnaround and offered to participate in and mastermind Toph's most dangerous and risky and visible AND STUPID scam yet. Things ended predictably enough FOR THIS CREW THAT MEANT THEY RAN AWAY WHILE LOTS OF THINGS BLEW UP AROUND THEM and the scam nearly came to a terrible end but during the trouble Katara admitted she really liked Toph and didn't want to fight with her and Toph in turn admitted that she really liked Katara and that's why she did want to fight with her and they hugged and apparently that was enough because they got along famously after that and all of their subsequent mudfights were friendly affairs that were purely for entertainment purposes.
"Zuko suggested Ty Lee and I have a mudfight once. The moron didn't stop bleeding for an hour."