"Lightning is a pure expression of firebending, without aggression. It is not fueled by rage or emotion the way other firebending is."
In the aftermath of the previous episode
, both groups of main characters take time to recuperate. Zuko aids Uncle Iroh in recovering from his wound at Azula's hands, and Iroh tries to teach him to generate lightning; when Zuko is unable to achieve the necessary mental calm, Iroh instead teaches him a technique to redirect
lightning, which he invented by observing Waterbenders. Aang also begins lessons, learning Earthbending from Toph. It's very difficult for him because Earth is an Airbender's polar opposite
; Airbenders go with the flow by nature, while Earthbenders tend towards directness and stubbornness. Thus, the title of the episode refers to both Aang and Zuko struggling to master attitudes and techniques that are psychologically and elementally opposite to their normal mindsets.
Meanwhile, Katara continues some of Aang's training as a counterpoint to his difficulty with Earthbending, whilst Sokka carries on the meat-and-sarcasm tradition by trying to hunt a baby sabretooth moose-lion.
- Advice Backfire: Katara suggests to Toph that rolling a huge boulder downhill at Aang might not be the best teaching method. Toph agrees... realizing the lesson would be more effective if Aang was blindfolded.
Toph: Thank you, Katara.
Aang: Yeah, thanks, Katara...
- Angrish: Sokka's reaction to Toph waking him up. In the script, he had actual lines, but the writers thought the VA's improvised Angrish was funnier.
- Bilingual Bonus: The title is a rough translation of what "kung fu" literally means.
- Bottle Episode: the animated nature of the show makes it less obvious, but it's one of the few (if not only) episodes in the whole run that involves no guest voice actors or characters.
- Butt Monkey: Sokka ends up trapped in a hole in the ground up to his fingers, left totally helpless all day long and late into the evening trying to get out. Although it never comes up, imagine if he had been holding in an urge to take a leak...
- Cool Teacher: Uncle Iroh teaches Zuko about redirecting lightning, because he's traveled the world and studied all four nations.
- Cub Cues Protective Parent: Sokka finds a baby saber-toothed moose-lion cub, and inevitably it's mama is near, and has to be fought off by Aang.
- Deadpan Snarker: Iroh gets a good one immediately after waking up, when Zuko tells him it was Azula's surprise attack.
Iroh: Somehow that's not so surprising.
- Die or Fly: Invoked by Toph when she rolls a huge boulder down a cliff at Aang to try and get him to earthbend. Aang defies the invoking by jumping out of the way. Played straighter later in the episode, when successfully stopping an angry Sabertoothed Mooselion gives him the proper "stand your ground" mindset needed for earthbending.
- Drill Sergeant Nasty: Toph's training methods are harsh and intense. It makes for a contrast with Katara's gentler approach.
- Aang to Zuko. Both are subjected to the same bitter work, but Aang succeeds where Zuko succumbs to his own sense of victimhood.
- Katara and Toph are this in addition to Opposed Mentors.
- Getting Crap Past the Radar: As Toph gleefully cracks nuts open with Aang's staff, he notes it's a delicate instrument, handcrafted by the monks. Toph answers that "it's not the only delicate instrument around here".
- Gilligan Cut:
Katara: I've been training Aang for a while now. He responds well to a positive teaching experience. Lots of encouragement and praise. Kind words. If he's doing something wrong, maybe a gentle nudge in the right direction.
Toph: Thanks, Katara. A gentle nudge. I'll try that.
- Ignored Epiphany: Sokka neither gives up meat and sarcasm after being saved.
- Instant Armor: Toph does this with rock while trying to teach Aang how to earthbend.
- Mama Bear: The mother Sabertoothed Mooselion.
- Meaningful Name: In addition to noting the obstacles both the protagonists and his parallel face throughout the episode, "Bitter Work" is also a rough translation of the term "Kung Fu".
- Misplaced Kindergarten Teacher: Katara comes across this way, advocating a very supportive and affirmative teaching style for Aang. Subverted in that it is appropriate for his childish personality.
- No Antagonist: The only sources of conflict in this episode are Aang and Zuko's blocks while learning. The closest thing to an antagonist the episode has is the mother Sabertooth Mooselion, and even it fails to qualify.
- Nothing Personal: Sokka tells this to the creature he wants to eat.
- Off Model: Despite the fact that she's blind, Toph leaves a hole for her eyes when suiting herself in rock armor, rather than for her mouth to breathe. The creators admitted this was an animation error.
- Personality Powers: One of the first episodes that addresses this issue, as Toph emphasizes the importance of how you have be "steady and strong" like rock in order bend rock to your will.
Aang: What if I came at the boulder from a different angle?
No, that's the problem. You've got to stop thinking like an Airbender. There's no "different angle," no clever solution, no trickety-trick
that's gonna move that rock — you've gotta face it head on.
- Plot Parallel: Between Zuko and Aang and their "bitter work".
- Rage Against the Heavens: Zuko's final scene involves him climbing a mountain and shouting abuse at a storm.
- Ridiculously Cute Critter: The baby Sabretoothed Mooselion. It's too young to have any of the traits that makes the creature usually so fearsome.
- Smite Me, O Mighty Smiter: During Zuko's Rage Against the Heavens he demands that the clouds strike him with lightning. It's not like the world as ever held back before.
- Stealth Mentor: While Toph is...hard to get along with, she intentionally tries to get on Aang's nerves by eating his food, taking and misusing his staff, and simply watched when him and Sokka were attacked by an angry wild animal. All of this, so that Aang gains the confrontational stance needed to earthbend.
- Teach Him Anger: Toph's strategy for teaching Aang to "stand his ground" like an Earthbender is to keep pushing his buttons until he gets mad enough to stand up to her. It works.
- Thicker Than Water: Zuko assumes Iron won't help him prepare to another encounter with Azula because of this. Iroh defies it.
Iroh: No, (Azula)'s crazy and she needs to go down.
- Training Montage: Aang learning earthbending!