After Mrs. Krabappel punishes Bart for breaking the class aquarium, Bart finds a personal ad and writes to his teacher under the guise of Woodrow, an imaginary lover that's everything Krabappel wants in a man. Meanwhile, Homer curbs his swearing after Flanders confronts him about his son, Todd, picking up Homer's profanity while building a dog house for Santa's Little Helper.
- Achievements in Ignorance: Homer manages to solve two problems simultaneously, each one solving the other! When trying to build a doghouse, he hurts and injures himself, causing him to cuss a lot. Marge suggests a swear jar. After several days of trying to build the doghouse using the swear jar, he eventually stops cussing, and gains enough change this way for Marge to buy a doghouse. (And a six pack of Duff.) In other words, the doghouse project helps him stop swearing and the swearing helps gain a new doghouse!
- All Just a Dream: In-universe with "A World Without Zinc".
- Angrish: Most of Homer's swearing turns into this.
- Bad Boss: The manager of the Twirl King Yo-Yo Company performers.Boss: Get your worthless butts in the van. We got three more schools to do! Let's go, go, go!
- In this case, the boss is correct because his assembly crew and all other sorts of assemblies like this one do multiple schools in one day.
- Bee Afraid: One of Homer's swearing incidents is caused by a beehive suddenly falling on him while he's relaxing in a hammock. We then cut to a hand covered in bee stings putting change in the swear jar.
- Berserk Button: Due to the sudden yo-yo craze, Edna develops a hatred of them.Edna: That's it! [slams book onto her desk] I am getting sick and tired of talking about yo-yo's. From now on, I will not accept any book reports, science projects, dioramas, or anything else on yo-yo's or yo-yo-related topics. Am I making myself clear?
- Bizarrchitecture: Homer's "attempts" to build a doghouse.
- Blatant Lies / Implausible Deniability: When Bart accidentally breaks the aquarium with his yo-yo, he tells Krabappel, "I didn't do it" while still holding the yo-yo.
- Bread, Eggs, Milk, Squick: "A World Without Zinc" teaches important uses for zink such as car batteries, phones and hand guns.
- Broken Aesop: It is better to let someone down easy after you've pulled a cruel, perhaps unforgivable prank on them. That is what Homer and Marge decide should be Bart's punishment for writing prank love letters to Mrs. Krabappel, rather than be real parents and force him to admit to both her and the principal, and possibly the superintendent as well what he had done and accept what surely would be severe consequences.
- Bungled Suicide: Played for laughs. Jimmy from "A World Without Zinc" is so horrified that he gets a gun to shoot himself in the head. He pulls the trigger, but nothing happens. He learns the firing pin was made of, you guessed it, zinc.
- Cool and Unusual Punishment: Bart's detention is him doing things Groundskeeper Willy should be doing like the plumbing and waxing the floor.
- Costume-Test Montage: Mrs. Krabappel tries a different outfit for her date.
- Curse Cut Short: Several from Homer ("Da-", "You sunofa-", "You dirty bast-," and "Aw..."). According to the DVD commentary for this episode (the first one, not the secret one), Dan Castellaneta actually went on several foul-mouthed tirades in Homer's voice during recording and the tirades were cut short on the track.
- A Day in the Limelight: For Ms. Krabappel.
- Detention Episode: Bart gets a month's detention when he plays with a yo-yo in class and accidentally breaks the fish tank.
- Disproportionate Retribution: Bart, rather than take responsibility for damaging school property and accept Mrs. Krabappel's punishment (which wasn't that severe), plays a cruel prank (creating a fictional love interest and writing fake love letters to her). That said, one could argue that Mrs. Krabappel's punishment was straddling the lines of this, although most likely the severe punishment she levies (a month's worth of detention) was out of exasperation from her being fed up with Bart's increasing misbehavior; after all, this is a guy who did things such as smuggle a knife into school, synthesize laxatives into carrots and stuff a lighted firecracker down a classmate's pants.
- Educational Short: Memorably parodied in the short Mrs. Krabappel shows the class about "A World Without Zinc". Trully a terrifying dystopia.
- Entertainingly Wrong: The family sees Bart writing a love letter, and assume he has a crush.
- Epic Fail: Homer building a dog house with no door to it. While it is physically possible to do something like that, the fact that Homer did (without noticing it before) shows the true depth of his ineptitude.
- Face Palm: Reverend Lovejoy has a glorious facepalm when his wife informs him that Ned Flanders is on the phone. Lovejoy would prefer to enjoy his dessert in peace and not to deal with Ned's latest "crisis."
- Forged Message: Bart creates a boyfriend for his teacher Mrs Krabappel and writes her letters based on his parents' old loveletters, pretending to be a guy called "Woodrow".
- Freeze-Frame Bonus: Gordie Howe's hockey stats at the end of the episode.
- Earlier, Todd holds up a figure that looks a bit like Toad.
- From the Mouths of Babes: Todd, after learning swear words from overhearing Homer.Maude: Would you like some mixed vegetables?
Todd: Hell no.
(everyone else gasps)
Maude: What did you say?
Todd: I said I don't want any damn vegetables.
Ned: Oh that's it, young man! No Bible stories for you tonight!
(Todd runs upstairs, crying)
Maude: You were being too hard on him?
Ned: You knew I had a temper when we married.
- Gosh Dang It to Heck!: An epic one from Homer, when he's mentally conditioned not to swear.
- Hidden Depths: It's Homer, of all people, that thinks of the ending for the love letter: "With a love that will echo through the ages."
- Idiot Ball: Couldn't Mrs. Krabappel recognize "Woodrow's" handwriting as being too similar to Bart's? And presuming that she has reasonable pop culture awareness, didn't she recognize the photo of "Woodrow" as ice hockey icon Gordie Howe? And what about his family not catching on that Bart wasn't exactly penning letters to a love interest?
- Innocent Swearing: When Todd Flanders first hears Homer's profanity, at dinner Todd Flanders says the swear words, not knowing how bad they are (he gleefully says "I said I don't want any damn vegetables!") But then Ned punishes Todd ("No bible stories for you tonight!"), and Todd, unaware of what he did wrong, starts crying as he goes to his room.
- Ironic Juxtaposition:Mrs. Krabappel: (in deep thought, while looking at Woodrow's picture) "When I read your letters, I feel as if you are right here watching me." (puts the picture down to see Bart in his desk staring at her) Bart, eyes down!
Bart: Yes, ma'am!
- Karma Houdini: Bart only broke the fish tank because Milhouse asked him for another yo-yo trick, yet Mrs. Krabappel doesn't bother to punish Milhouse for his role in the smash.
- Love Letter: Bart and Edna write several love letters to each other. Bart asks for tips from his whole family, and Marge shows Bart a love postcard she got once from Homer.
- Major Injury Underreaction: Homer does this after training himself out of swearing. Stepping on a nail, he says "Fiddle-de-dee. That will require a tetanus shot."
- Momma's Boy: When Bart asks why she doesn't try dating Skinner, Edna remarks "His mommy won't let him out to play."
- My God, What Have I Done?: Bart is guilt-stricken when he sees how upset Mrs. Krabappel is.
- No Celebrities Were Harmed: Harry Shearer based "Woodrow"'s voice on Ricardo Montalban.
- Prank Date: Bart's very cruel "no show" practical joke he pulls on his teacher.
- Sir Swears-a-Lot: Homer displays quite the foul mouth in this episode.
- Swear Jar: Marge makes Homer put money in it for foul language because one of the Flanders little boys picked it from him. Eventually, the family just buys a doghouse with the money from the swear jar.
- The Stinger: The episode ends with a trading card-style rundown of the hockey career of Gordie Howe, Woodrow's face; this was a creative way of filling a slight time under-run.
- Throw the Dog a Bone: Homer goes through all sorts of painful humiliations and misfortunes as he tries to build the doghouse, among other thing, and loses a lot of money to the Swear Jar in the process. It ends up paying off when Marge uses the money put into the swear jar to just buy a new doghouse, alongside some beer for Homer.
- Two Words: Added Emphasis: Homer's suggestion for a break-up letter for Mrs. Krabappel is "Three simple words: I am gay."Marge: For the last time, I'm not writing that!
- What the Hell, Hero?: Marge calls Bart out for writing a fake love letter. Homer tries to do the same thing by telling Bart to tell the truth about the letters, but Marge tells Homer that they can't do that since Edna would be humiliated (never mind the fact she already was humiliated). Homer only said it because he thought Marge would expect him to.