After realizing how much of an embarrassment he is when he's drunk, Barney decides to go sober and stay sober, which doesn't sit well with Homer. Meanwhile, Bart and Lisa enter a photography contest.

!! Tropes:

* TheAlcoholic: Barney drinks so much that Duff Brewery workers once posed for a photograph with a sign reading "Thank you, Barney".
* AluminumChristmasTrees: Homer goes to the Kwik-E-Mart and asks Apu for "those potato chips that give you diarrhea". Apu then returns with bags of what appear to be ordinary Ruffles. This was based on a real-life product known as Lay's WOW Chips introduced a couple years before the episode aired, which famously contained the chemical olestra, a known stool loosener.
* CallBack: Bart and Lisa create their own rendition of [[Recap/TheSimpsonsS5E5TreehouseOfHorrorIV ''A Friend in Need"]] with Santa's Little Helper taking part.
* DiabolusExMachina: Just as Bart and Lisa attempt to take their picture of dogs playing poker, Nelson steals their photo at the last second.
* ForgottenBirthday: Barney thinks his friends forgot his birthday but it's him that, due his alcoholism, forgot the party.
* MustHaveCaffeine: Since Barney won't be purchasing beer anymore, Moe starts selling coffee and get him hooked on double mocha lattes.
* MyGodWhatHaveIDone: Barney is legitimately disgusted with himself when he sees footage of how he acts when he's drunk, such as harassing Lisa and, somehow, breaking into the Simpson house dressed as and thinking he's Marge before he falls off the stairs and tries lapping up spilled beer on the floor.
* NoodleIncident: Barney has an arm handcuffed to a police car door and doesn't remember how or when it happened. His friends say they can't imagine him without it.
** As mentioned in PaperThinDisguise, there's a scene where Barney shows up in the Simpson house dressed like Marge. How he managed to get in and how he ended up dressed like that aren't given specific details other than he was drunk.
* PaperThinDisguise:
** During a videotape of Barney's birthday party, there's a scene where he's dressed like Marge. Homer initially mistakes him for the real Marge.
** A TV ad about a photography contest features a "mysterious prize". The wrapping's shape makes it obvious that the prize is a bicycle. A kid shows up and rides the still wrapped bicycle.
* StatusQuoIsGod: Subverted. Barney stays sober for several seasons after this.
* TemporaryBulkChange: Bart insists towards Lisa that the only photos people care about feature celebrities at their worst. As if on cue, a fat Rainier Wolfcastle walks out of the Kwik-E-Mart with an armful of junk food, claiming he's preparing for a fat secret agent role.