There's an undisputed king of all Avatar: The Last Airbender gags and, no spoilers, but it involves mountains of green produce. However, many other gems are also sprinkled throughout the show that it would be a major shame if the new live-action Netflix series fails to include.
Though unintended, most of these gags represent the various undercurrents of the series, often utilized to accompany deeper themes and character arcs. They helped inject humor into the different situations, and Avatar wouldn't be the same without them.
Zuko's Anger
Zuko didn't fully resolve his anger issues until "Sozin's Comet." And needless to say, his character was the butt of a lot of "angry" jokes both outwardly, by the creators, and inwardly, by the other characters. Sokka jokes about his anger problems all throughout "The Firebending Masters," and in "The Ember Island Players," Zuko angrily says "how could you say that!" to Katara after she tells him the actor's humorless portrayal was spot on—only for the actor to say his exact line seconds later.
Sokka jokes about his anger problems all throughout "The Firebending Masters," and in "The Ember Island Players," Zuko angrily says "how could you say that!" to Katara after she tells him the actor's humorless portrayal was spot on—only for the actor to say his exact line seconds later. It was always fun when the show joked about Zuko's anger, as it formed a cornerstone of his character, and it was a nice way to lighten this more serious trait.
Katara And Hope
As the perceived "mom" of Team Avatar, Katara was often the stricter and more task-oriented member of the group. In episodes like "The Runaway," the characters made fun of these qualities, and it became a joke both in the series and within the fandom that Katara could get a bit moralizing sometimes.
"The Ember Island Players" really opened the floodgates on the "hope" part of the joke as well. And since the writers created the episode to poke fun at themselves, it revealed a lot about how they perceived Katara, as the actress who portrayed her went on a nonstop tirade about hope through the entire play.
Hot Leaf Juice
Uncle Iroh's obsession with tea was a major facet of the series. His love was established in the premiere episode "The Boy in the Iceberg" when he tells Zuko to enjoy a "calming cup of jasmine tea," only for the hot-headed teen to angrily shout "I don't need any calming tea!"
Iroh later cries over a spilled cup of tea in "The Secret of the Fire Nation," and there are multiple humorous instances involving tea in Ba Sing Se that make fun of his love for the beverage. Including, of course, Zuko's infamous "hot leaf juice" comment. It was a great way to establish their playful relationship, and his obsession was one of the best running jokes from the series.
Sokka's Artistic Side
Also hailed as one of Sokka's "hidden talents," the writers of Avatar loved to both build up Sokka's artistic tendencies and, equally, make fun of the sort of art he could produce. His painting in "Sokka's Master" and special knot in "The Library" are good examples of how funny his artwork could be, but his drawing in "Day of the Black Sun" is the best example of this contrast between his intelligence and rather poor artistic skills.
It's revealed that he actually conceptualized the submarines that the Mechanist built, but his nearly intelligible stick figure drawing is then shown, and it's a very funny moment. These drawings were a nice pairing to his sarcastic personality, as they were a way to provide visual gags in addition to his humorous comments.
Momo Shenanigans
Momo was always getting into trouble. He was either battling it out with a baby like in "Return to Omashu," or he was accidentally participating in a circus, like his debut act in "Tales of Ba Sing Se." He was always a great source of physical comedy, and his shenanigans brought a lot to the series.
He was also very food-based, like Sokka, and their dual obsession with eating was a great running joke during Team Avatar's adventures.
Sokka And Food
Sokka and his food habits were a large part of his character. So much so, that his actor in "The Ember Island Players" only made food jokes during the entirety of the play. Evidently, that's the side of Sokka that everyone remembered most when the fictional play researchers interviewed people who had met him.
In "Bitter Work," his vow to never eat meat again was a funny joke throughout the episode, and his reactions to food such as the fire flakes in "The Deserter" brought a lot of comedy to his character. The series wouldn't be the same without this running gag, and it's what makes Sokka one of the most lovable characters.
Hybrid Animals
The strange combinations of animals were a large part of the world-building in Avatar: The Last Airbender, and though they helped distinguish it as its own, the combinations got a little out of hand. Each episode seemed to be trying to outdo the last, and according to Bryan Konietzko in the Avatar "Art of the Animated Series," this was a purposeful joke by the writers.
He thinks that the hybrid pigs in "Zuko Alone" is perhaps the biggest reach they ever made, as there was a pig-cow, pig-rooster, pig-deer, and pig-sheep. And in "City of Walls and Secrets," a big running joke was the kid's disbelief that the Earth King had a pet bear, not a hybrid. The simultaneous comedy and intrigue that the hybrid animals brought truly distinguished the series, and it was a great way to inject a little subtle humor.
Toph's Blindness
Toph's character was a great example of how disability can be represented in television, and though the creators showcased many empowering instances around Toph's blindness, there were plenty of jokes as well. Her inability to see was a large source of humor in "The Runaway," as well as in "The Ember Island Players."
The actor who portrays her character in the play tells the audience he can see through his mouth, and after yelling for a few minutes, he says, "There, I got a pretty good look at you." It's a funny and obvious play off her ability to see through her feet, and it cracked Toph up just as much as the audience watching the episode.
Zuko's Honor
Azula cracked an honor joke in "The Chase," Zuko poked fun at his famous catchphrase in "The Boiling Rock," and it was a large source of humor in "The Ember Island Players." Needless to say, while the phrase "I need to regain my honor" began as rather sinister and mysterious in the first season, it ended as a running joke due to Zuko's character arc.
By the third season, he didn't need his honor anymore, and it was a nice way to indicate this change in his character by making the phrase more of a joke, and an homage to all the progress Zuko had made.
My Cabbages!
It's the big one, at last. The cabbage man and his cart followed the gang all over the Earth Kingdom, appearing in towns like Omashu, the pirate port, and Ba Sing Se, and his shtick was always the famous "My cabbages!" after his cart was destroyed inadvertently by the kids in some way or another.
It was an amazing visual gag, and his cabbages have become a staple iconic food of the Avatar universe. The running gag even made it into The Legend of Korra, with the famous phrase morphing into "My cabbage corp!" after the company was seized by the police. It's a fan favorite, a classic, and a great one-liner.