Santa's Little Helper is agitated by the sights, sounds, and smells of the Simpsons' Christmas celebration: he refuses to be affectionate, tears apart the couch, and stares idly at a smudge on the cabinet. Lisa suggests attending a seminar from dog psychologist Elaine Wolff. Wolff mostly berates dog owners and her talk is not helpful, but when Lisa tries to ask her to help the Simpsons to empathize with Santa's Little Helper, she explains that they are underestimating how his sense of smell is strongly tied to memory and it brings back memories of when he was an abused racing dog. When Marge reaches for a Santa Claus hat that the dog has been keeping next to him, he nips at her.
Bart insists on sleeping outside with the dog overnight. The next day, they take him to an incompetent vet who wants to euthanize him. He calls the police and Chief Wiggum comes to their house with a dog exterminator close behind. Moments before animal control is set to arrive, Wolff appears at the door saying that she has had a revelation and wants to save him.
She runs off with Santa's Little Helper and they go to her therapy institute where she has an opportunity to communicate with him. She determines that the event causing his post-traumatic stress disorder goes back to his childhood and she sets out to find his origin. At the No Kill Kennel, dog trainer Les Moore explains how he took Santa's Little Helper from his mother She-Biscuit because he ran to her so quickly. The family is outraged, but their hearts are quickly warmed when the mother and son are reunited in Moore's yard. The Simpsons adopt She-Biscuit and give her a happy home.
- 0% Approval Rating: Everybody slaps SLH's previous owner, from Elaine to each of the Simpsons. Homer even holds Maggie up to his face so she can get a slap in.
- Absurdly Youthful Mother: Between the flashback to SLH as a puppy and the present, there's no change in his mother's appearance.
- Aspect Ratio Switch: The Call-Back to the dog track is taken from the very first episode, and as such, is presented in its original 4.3 aspect ratio with the edges slightly blurred.
- Bad People Abuse Animals: Les Moore by his own admission tortures animals, and everyone agrees that he's complete scum.
- Bait-and-Switch: Played twice with Abe. First, we see the family from Santa's Little Helper's perspective, with each of them speaking gibberish: when we switch back to third-person, we find out that Abe really was speaking gibberish. Then a Flashback... Back... Back... moment reveals that Abe really did repeat the same word three times (he was asking for more pills).
- Better with Non-Human Company: The dog psychiatrist, Elaine Wolff, treats dogs with kindness and understanding, but is nothing but rude to their owners. She also keeps spurning a suitor's attempts to propose to her because she's too busy with her canine clients.
- Big Brother Instinct: As a nursing pup, SLH notices a sibling having trouble reaching their mother's milk udder and helps them reach it.
- Biting-the-Hand Humor: Homer after putting on the Cone of Shame.Homer: I feel like the Pixar logo.
- Call-Back: The dog track race from the very first episode is a major plot point. There's even a flashback showing the sudden shift in art style.
- Christmas Episode: In-universe, the episode is set during Christmas, most likely to reflect how Santa's Little Helper was abandoned on Christmas Eve.
- Comic-Book Time: Functions as a Sequel Episode to "Simpsons Roasting on an Open Fire," which took place on a preceding Christmas.
- Cone of Shame: Homer puts one on so he won't look the veterinarian in the face for suggesting putting SLH down.
- Crowded-Cast Shot: Played for Laughs. Marge tells Santa's Little Helper he's out of the Christmas card but quietly reassures the kids that he isn't: when Bart asks if he and Lisa can be out of the card, she snaps, "Everyone's in the card!" Lisa then expresses hope that Marge doesn't mean "everyone" like she did last year—gesturing toward a card that's one of these.
- A Day in the Limelight: The episode focuses on Santa's Little Helper.
- Food Slap: When Elaine insults the trainer, he sarcastically offers her a drink to throw at his face. She takes him up on the offer.
- Flashback... Back... Back...:Marge: He seems to be staring at that smudge... smudge... smudge...
Lisa: There's something wrong with our dog... dog... dog...
Abe: I need my pills... pills... pills... Three pills. - Funny Background Event: As Elaine speaks about SLH, you can see Sideshow Mel giving his hair bone to his dog before driving away.
- Gift-Giving Gaffe: Homer's presents to Marge are a vacuum, mop, bucket, and first aid kit.Marge: Homer, we need to talk about the difference between gifts and cleaning supplies.
- Insult Backfire: Bart calls Chief Wiggum a "big blue balloon", he actually likes the image and imagines himself as a parade balloon.
- Jerk with a Heart of Gold: Homer is furious about SLH biting Marge, but refuses to have him put down and likewise doesn't take too kindly to the previous owner's treatment of him.
- Karma Houdini Warranty: Les Moore gets slapped 7 times and bitten by Santa's Little Helper.
- Once More, with Clarity: SLH's past as a race track dog and abandonment on Christmas Eve is given more depth.
- Pet the Dog: Almost a literal example as Homer showers SLH with kisses. At first the family dog doesn't seem receptive to Homer's affection... before licking him, showing that he does appreciate it.
- Something Something Leonard Bernstein: Homer clearly doesn't know all the lyrics to "Jingle Bell Rock" and mostly just repeats the name over and over.
- Trauma Button: SLH panics when a Santa hat is nearly placed on his head and later freaks when Marge tries to take it away to clean it, which leads to him biting her. Elaine does tests to determine the hat is indeed the cause of this, and Bart later recognizes it as the one he was wearing the night SLH was chased away by his previous owner. Elaine surmises the hat reminds SLH of the awful ways he was treated before being adopted by the family.
