Context: When Homer lands the role of "Poochie," he and his Itchy & Scratchy co-star field a bunch of nitpicky questions from the show's nerdy superfans, including, before this quote, one fan recalling an episode where Itchy played Scratchy's ribs like a xylophone but the same rib managed to "magically" produce two completely different tones.
Useful When: Someone's unnecessarily nitpicking a movie or tv show that's obviously supposed to be fun. Or you're doing it yourself and knowingly calling yourself out.
Context: During a Springfield teachers strike, a back and forth argument between Mrs. Krabapple lobbying for more funding and Principal Skinner reminding people they'd have to raise taxes eventually devolves into Krabapple just saying "cahmmannnnnn" and Skinner replying with this finger gesture (the finger thing means the taxes).
Useful When: Someone suggests doing anything way too expensive (mediocre concert, overpriced restaurant, etc.)
Context: Homer's plan for what to do during his big final exam that he hasn't prepared for.
Useful When: You have absolutely no idea what you're doing in a particular situation and you aren't going to fight it.
Context: Bart's perfectly understated reaction when he sneaks onto a roller coaster he isn't tall enough for and the safety bar immediately closes over his head.
Useful When: You need a catch-all response for when anything very obviously bad happens.
Context: When Marge finds and old party sub behind the radiator and tells Homer "I really think you should throw it away," Homer briefly acknowledges her logical advice before immediately eating the rancid sandwich.
Useful When: Someone makes a suggestion (good or bad) that you're clearly going to ignore.
Context: When Lisa gives an impassioned speech on local tv about appreciating your intellect, the studio technician goes to cut off her mic and is stopped by her manager saying "No no...let her speak. I'm trying to get fired."
Useful When: A public figure (sports coach, political candidate, a brand's social media person) makes an overwhelmingly bad decision.
Context: Moe ridicules Homer for his extremely fancy usage of the word "garage" (instead of carhole).
Useful When: Someone's trying to sound fancy by using a bunch of not-really-all-that-fancy words.