After getting busted on a DWI ("driving while intoxicated," not DOA ["dead on arrival"], as Chief Wiggum learned) chargenote after sneaking out of work to go to a Duff Beer Factory tour, Marge urges Homer to go 30 days without beer. Meanwhile, Bart destroys Lisa's steroid-injected tomato and becomes an unwitting test subject in her new science fair project: "Is My Brother Dumber Than a Hamster?"
- Alcohol Is Gasoline: Whilst struggling with temporarily giving up alcohol in Season 4 episode "Duffless", Homer spot's Ralph Wiggum's science project of an alcohol fueled car. He immediately has an Imagine Spot of him pumping "fuel" into both his car and his mouth.
- Bait-and-Switch: Just as it appears Lionel Hutz is going to help Homer out of his jam, it turns out that the Amoral Attorney is actually his neighbour in prison.
- Bedtime Brainwashing: The episode opens with Principal Skinner awarding Bart first prize at the school science fair. The phrase "first prize" echoes until the scene transitions to reveal that Lisa was saying this into Bart's ear while he was dreaming because she was "just screwing with [his] mind."
- Bill... Bill... Junk... Bill...: Man checking beer bottles at the Duff Brewery: "Fine, fine, mouse, fine, mouse, rat, fine, syringe..." And then shortly after that, while the checker is distracted by Barney, Adolf Hitler's head goes by!
- Black Comedy:
- Bart chucking Lisa's steroid-pumped tomato at Principal Skinner (who is a Vietnam vet who has moments of post-traumatic stress disorder from his stint in 'Nam and the abuse his mother puts him through) and Skinner shaking in shock while the kids laugh at him.
- Chief Wiggum confusing DWI with DOA, especially when a woman comes in asking if her husband was here on a DWI and Wiggum quickly leaves on a lunch break.
- Homer laughing at the montage of car wrecks (and Troy McClure's attempts to make jokes during it- "Here's an appealing fellow; in fact, they're a-peeling him off the sidewalk!").
- Borrowed Catchphrase: Bart says "D'oh!" when Lisa manages to find her science project after he hides it.
- Broken Aesop: Invoked in-universe. An ad outside the Duff Brewery says: "Friends don't let friends drive drunk" before it switches to a Duff ad depicting two friends drinking beer on the hood of a car. Homer putting this message into action also causes the episode's dilemma.
- Comic-Book Time: Ned Flanders says it's been 4,000 days since his last drink. Four thousand days is almost 11 years, but Ned makes it sound like his bad event that made him join Alcoholics Anonymous only happened yesterday.
- Cold Turkeys Are Everywhere: Homer tries and fails to escape Duff advertising, to the point where a blimp bearing the sign "Surrender to Duff" airdrops beer bottles directly onto him.
- Crack Defeat: Lisa decides to use Bart as a guinea pig for a science project (out of spite for him ruining her original one on a practical joke) dubbed "Is My Brother Dumber Than A Hamster?". When it comes time to show her results at the fair, she's shown up and actually beaten by Bart who simply dresses up a hamster with a tiny scarf and goggles, puts him a model plane and appeals simply for the cute factor.
- Cuteness Proximity: Bart exploits this with his "Can hamsters fly planes" project. No one questions how relevant or scientific the project is because of the endearing diorama of a hamster in a toy plane.
- Cutting the Knot: Rather than try to answer the spider, Homer just chucks a rock at his head and jumps out the window.
- Every Car Is a Pinto: This even applies to mascot costumes, as Police Chief Wiggum finds out the hard way.
- Deliberate Values Dissonance: One Duff Beer ad from the 1950s has a cartoon doctor advising the viewers to drink the beverage because of its "goodness", but also indicates the company is also a "proud sponsor" of Amos N Andy, a very popular radio and (briefly) TV show that ran between 1928 and 1960 mostly remembered nowadays for being an example of Blackface (even in spite of being quite Fair for Its Day).
- Disproportionate Retribution: What's Lisa's way to pay Bart back for "bustin' [her] tomater?" Psychological torture via electroshock to exploit him and try to win the science fair. She loses to Bart but in all honesty, she more or less deserved to lose.
- Fair Weather Friend: Homer goes back to Moe's who is happy to welcome him despite badmouthing him the day before.
- Get Out!: Reverend Lovejoy assures Homer that he won't be shamed for his past actions at the AA meeting, but when Homer admits that he was so desperate for beer he snuck behind the bleachers and ate some dirt (likely being spilled by beer):Reverend Lovejoy: I CAST THEE OUT!
- Giant Spider: One of these guards the way out of the plant via Sector 7-B. The directions Homer was given say "To overcome the spider's curse, simply quote a Bible verse", but after saying a fumbling "Thou shalt not—", Homer gives up and drops the spider with a well-placed rock to the head.
- Grey-and-Gray Morality: Bart destroyed Lisa's giant tomato that she had grown for the science fair. However, Lisa's retaliation is to use Bart as a guinea pig for an experiment designed specifically to humiliate (and psychologically damage) him, so she's no saint, herself.
- Imagine Spot: Lisa has one where, thanks to her initial project, she's so famous that a family in India has a picture of her, ostensibly as a Messianic Archetype.
- Incompetence, Inc.: Duff Brewery has had Strychnine contaminations (which it unconvincingly denies), the quality control guy finds rats and syringes in their bottles and gets distracted easily, all its beer brands are exactly the same drink, and the tour guide point-blank admits when pressed that they have no ideas for the future.
- Ironic Echo: At the start of the episode, Skinner declares "First Prize!" for Bart's science fair project, which turns out to be a dream Lisa is causing just to screw with him. At the end of the episode, Skinner awards Bart first prize for real, and to rub salt in the wound it was a response to Lisa doing a project specifically to make him look dumb.
- Jerkass Ball: Lisa holds the ball pretty firmly in this episode starting from her first act which was to more or less screw with Bart's dream for no real reason other than It Amused Me. She briefly drops it when Bart throws her tomato at Skinner's behind but she picks it right back up when she decides to switch her experiment to be nothing more than to torture Bart for revenge.
- Karma Houdini:
- Barney gets away with essentially kicking off the episode's main plot by urging the police to give Homer a breathalyzer test right after he flawlessly passed a field sobriety test (granted, Homer beat Barney pretty bad in order to dissuade him from driving). After failing the breathalyzer test, the clearly sober-enough-to-drive Homer is arrested, stripped of his driver's license, forced to attend AA meetings, and gets into a bet in which he can't drink beer for a month; meanwhile, the obviously skunk-drunk Barney is allowed to drive off, even knocking one of the cops off a cliff as he speeds away.
- We don't see Skinner punish Bart for throwing a giant tomato at him though it's likely because he was too traumatized on screen to do so. To add insult to injury, when Lisa does try to get back at Bart, it backfires as he triumphs over her automatically at the science fair. (That said, he did end up traumatized by electric shocks.)
- Laser-Guided Karma: Wiggum arrests the still relatively sober Homer, and allows the very clearly drunk Barney to drive home without doing any tests on him. He's immediately knocked off the road by Barney and sent rolling into a tree before inexplicably blowing up.
- Lisa gets this thrown right back at her when she loses the science fair to Bart after using her experiment to more or less torture him psychologically with electric shocks. Sure, she worked on that tomato for a long time but the overall retribution is rather disproportionate.
- Leaning on the Fourth Wall: At the end of the episode, when Homer leaves Moe's bar to go on a bike ride with Marge, Moe proclaims "You'll be back. And so will all of you, and you... and you," whilst looking and pointing directly at the viewer, before quickly cutting to a different shot to show he was talking to Barney.
- Made of Explodium: Chief Wiggum's beer-stein costume. (He's OK after the commercial break.)
- Made of Iron: In order to prevent him from driving drunk, Homer punches Barney in the face, clubs him with a crowbar, and slams the car door on his head five times to no effect.
- Minor with Fake I.D.: Homer sings a version of "It Was a Very Good Year" by Frank Sinatra, changing the lyrics thus:"When I was seventeen,I drank some very good beerI drank some very good beer I purchasedWith a fake IDMy name was Brian McGee..."
- Mood-Swinger: When Homer visits Moe's towards the end of the episode:Moe: Well look who it is. Mr. "I don't need alcohol to enjoy life." We hate him, right, fellas?
(bar patrons murmur in vague agreement)
Homer: Moe, gimme a beer.
Moe: (pleased) Hey everybody, Homer's back!
(bar patrons murmur in vague agreement)
- Never My Fault: Let's be honest here. Sure Bart was at fault for ruining Lisa's science project, but if you're dumb enough to trust a person like Bart of all people to hold your project for you — especially knowing full well what's going to happen since you've known him all your life — then you're officially just asking to lose the science fair.
- Obnoxious In-Laws: The "void" stamping on Homer's license is done by his sister-in-law Patty, who's very pleased about doing it.
- Oh, Crap!: Homer confuses his internal and external monologues at breakfast before going to "work" and thence to the Duff Brewery.Homer's Brain: Well, off to the Plant.
Homer: (slyly) Then to the Duff Brewery.
Homer's Brain: Did I say that or just think it?
Homer: I gotta think of a lie, fast!
- Only Smart People May Pass: Bart hides Lisa's report and dares her to find it by deciphering a fiendish series of clues ... only for Lisa to find it before he's finished gloating.
- Parent Produced Project: One boy's father made his science fair model volcano for him and snaps when he asks to adjust it himself. It's also virtually certain that somebody else (if perhaps not his almost as dumb parents per se) made Ralph's alcohol-fueled car for him.
- Poke the Poodle: Ned has consigned himself to Alc-Anon meetings for over a decade. Why? Because he drank a blackberry schnapps, and while mildly inebriated, called Ann Landers a boring old biddy."I was more animal than man!"
- Police Are Useless:
- Wiggum mixes up DOA and DWI.
- Wiggum arrests Homer for driving while drunk, but then allows the even drunker Barney to drive the car home.
- Screw This, I'm Outta Here!: One Mrs. Phillips shows up at the police station and tells Chief Wiggum she's there because someone called and said her husband was found DWI. Realizing it's another of his usual DOA/DWI mixups, Wiggum directs her to other cops and leaves for lunch.
- The scene where Bart can't bring himself to touch two cupcakes (which look like women's breasts) is a reference to A Clockwork Orange.
- The 1950s-era ad shown at the Duff Brewery mentions the company was a "proud sponsor" of the Amos 'n Andy TV show.
- Another of the ads (apparently partway through Richard Nixon and John F. Kennedy's 1960 presidential debate) has JFK singing Duff's praises, drawing cheers from the audience. Nixon's more halfhearted endorsement is loudly booed in contrast (Homer: "The man never drank a Duff in his life!").
- Soundtrack Dissonance: The gruesome driver's ed film is accompanied by the goofy stock music piece "Round the Bend".
- Status Quo Is God: Anyone who is vaguely familiar with The Simpsons knows that Homer's sobriety is shortlived (he's back the drinking the next episode). It dampens the heartwarming ending on rewatch. Admittedly, his goal wasn't to stop drinking entirely, just to show he could survive without it and stop being the near-alcoholic he was.
- Suspiciously Specific Denial: The Duff tour guide announces at the start that he's going to address the recent news story that a batch was contaminated with strychnine. When everybody on the tour admits to having no idea what he's talking about, he hastily says that it's not true and moves on.
- Take Our Word for It: Obviously, we do not see the multitude of car crashes in the film that Homer and his AA class watch. We can still imagine the horror of it all, given the sounds of the crashes (the offensive Soundtrack Dissonance aside) and the reactions of the class (which range from shock, disgust and fear, save for Homer, who finds it funny since he doesn't know any of the victims).
- Take That!:
- Homer tries to watch a ball game during his "dry spell", finding the whole business boring.
- When snickering at the thought of having revenge on Bart, Lisa tells Marge that she remembered a bit from Herman's Head. Marge looks on worriedly, probably more than if Lisa had told her the truth. Also an example of Self-Deprecation, since several Simpsons cast members (including Lisa's voice actress Yeardley Smith) were regulars on Herman's Head.
- Three Stooges Shout-Out: Bart imitates two of the Three Stooges when he tries to grab the cupcakes and gets zapped. Later, when Lisa asks him to hold her giant tomato while she fetches her math book, he replies, "Why, soitenly! Nyuk, nyuk, nyuk!"
- Troubled Fetal Position: When Bart can't bring himself to grab the cupcakes, he ends up curling up in a ball.
- Younger Than He Looks: Hans Moleman is revealed to be 31 years old and looks old because of severe alcoholism. Before anyone cries "Negative Continuity!", this ties in with the birth date on his driver's license, as seen in "Selma's Choice," which is August 2, 1961 (which would make him around 31 to 32 years old at the time of this episode's premiere).