What An Idiot / The Simpsons

Much of the humor from the animated series The Simpsons comes from the characters failing to recognize their own stupidity, being clueless when others harshly criticize them and so forth, so take this with a heavy dose of Tropes Are Not Bad. Note: There seems to be a reoccuring theme where the characters' stupidity is increased in the Non-canon Treehouse of Horror episodes to the point where it does themselves in as the plot requires it so.

  • Early in the series' run, a popular recurring gag was "Prank Calls to Moe," where Bart would call Moe's Tavern and ask the hapless Moe for someone whose name, when yelled out, was a double entendre.
    You'd Expect: Moe to quickly if not immediately catch on—since he knows Bart and thus recognizes his voice—and have the police arrest him.
    Instead: (1) Moe never seems to realize that it is Bart who is calling. (2) Moe falls for the joke every time (e.g., "Do I have a B.O. Problem?"). Once someone responds or the bar laughs uproariously, Moe–-rather than ending the call and immediately calling the cops—threatens the culprit with severe harm.
    • Possibly the most egregious lapse in Moe's intelligence comes in the Season 3 episode "Burns Verkaufen Der Kraftwerk," when (1) Moe recognizes Bart's voice (Bart having been sent to Moe's by Marge to collect Homer) and (2) Bart even announces his presence with the very words he tended to call the bar with ("Excuse me, I'm looking for …"), but instead has him sing for the bar.
  • In the very first episode, "Simpsons Roasting on an Open Fire", Bart wants a tattoo for Christmas despite Marge's objection. At the mall, Bart sees the tattoo parlor has one of a heart with the message "mother" underneath and thinks it will convince Marge otherwise. He walks inside where the artist suspects that he is underage. Upon being asked how old he is, Bart insists that he's 21.
    You'd Expect: The artist to immediately suspect that Bart is lying and deny him service. At the very worst, he could check Bart for proof of identification which someone of his age obviously may not even have.
    Instead: "Get in the chair."
  • In the opening gag to the Season 4 episode "Homer's Triple Bypass," a parody of COPS, Chief Wiggum and the Springfield Police Department is called to a report of numerous cattle in a yard in a residential neighborhood. The National Guard(!) is called in to provide a tank to break down the door of the suspect.
    You'd Expect: The officers to respond to the correct address—742 Evergreen Terrace—even if by seeing the cattle in the yard of the suspect's address.
    Instead: They break down the door of the neighbor's house—the one belonging to Rev. Lovejoy. As a very angry Lovejoy tries to explain to the officers that they have the wrong address, the scene shows an empty yard, before panning to the neighbor's yard, which has the cattle. The actual suspect—Snake—taunts the officers and makes his escape.
    • So now…
      You'd expect Chief Wiggum to at least be able to read a license plate and accurately describe either Snake (a well-known criminal in Springfield, whom Wiggum and/or other officers on the force have arrested several times) or at the very least his car when putting out the all-points bulletin.
      Instead: Wiggum fails to provide even a very vague description: "Put out an APB for a male suspect, driving a… car of some sort, heading in the direction of… you know, that place that sells chili. Suspect Is Hatless. Repeat, hatless."
  • Season 4's "Krusty Gets Kancelled" includes a scene where Mayor Quimby – running for re-election in a cutthroat campaign – freely admits to the press that he had looted Springfield's finances to arrange the murders of his political enemies. He diverts attention by quoting the catchphrase of ventriloquist's dummy Gabbo (the episode's Villain of the Week), "I'm a bad wittle boy!" and all is forgiven.
    You'd Expect: With several police officers standing nearby, for Quimby to quickly be arrested.
    Instead: The police do nothing as the press corps and others in the large crowd cheer wildly for Quimby. Not only is he never taken into custody, but Quimby easily wins re-election, even as more bodies begin surfacing in Springfield Harbor and nobody asks questions.
  • In the Season 5 episode "Cape Feare":
    • Sideshow Bob, serving a prison sentence, is up for parole.
      You'd Expect: With numerous witnesses having testified against him and overwhelming evidence that he sent threatening letters to Bart (including several written in his own blood), the parole board to quickly and decisively deny Bob parole.
      Instead: Bob is paroled. Later in the episode, the Simpsons have to be placed in the Witness Protection Program.
      Worse: The parole board clearly sees that Bob has a tattoo saying "DIE BART DIE", and Bob claims that it's supposed to say "THE BART THE", but it's just in German, which is not entirely wrong. The parole board then consideres this a point in Bob's favour, believing that no-one who speaks German could be evil. It's as if they've never heard of this guy.
    • Still, Bob is able to stalk the family and eventually tracks down Bart on the Simpsons' houseboat and corners him.
      You'd Expect: For Bob to just simply kill Bart and complete his revenge.
      Instead: Bob arrogantly asks Bart if he has any last requests, giving Bart the opening he needs. Bart requests that Bob sing to him the entire score of H.M.S. Pinafore. Bob complies… and the score is long enough to give the pilotless, drifting houseboat to run aground, knock Bob of the boat and stun him long enough for the authorities to arrest him.
  • In the Season 5 Halloween episode, Homer decides on a whim to sell his soul for a doughnut, however just as he's down to the last piece, it's revealed that he keeps his soul if he doesn't finish the whole thing.
    You'd Expect: Homer (or really, Marge or one of the kids) to throw the doughnut away, preventing the devil from taking his soul.
    Instead: They keep the doughnut piece in the fridge; when Homer goes to the kitchen at night for food, the predictable happens. Homer manages to keep his soul, but gets a giant doughnut for a head.
  • In Season Five's "Bart Gets an Elephant", Homer allows people to see Stampy for a price. But with $1 to see, and $2 to ride, he's not making enough to cover any of Stampy's bills. So, he jacks up the prices.
    You'd Expect: Homer to perhaps charge no more than $5 to see and $10 to ride.
    Instead: "See the Elephant: $100, Ride the Elephant: $500". Screw This, I'm Outta Here!.
  • Season 6's "Sideshow Bob Roberts": Republican talk show host Birchibald T. Barlow talks to Bob, who was imprisoned for trying to murder Bart the last time we saw him. Bob claims that, since he's serving time for attempted murder, he's been convicted for a crime he hasn't committed.
    You'd Expect: Barlow to not buy it even for a second; Bob may not have committed murder, but he would have done so if Bart hadn't foiled him.
    Instead: Barlow sympathizes with Bob, due to the two of them both being Republicans, and convinces the people of Springfield to push for his release. Bob is subsequently set free, whereupon he proceeds to cheat his way to becoming Mayor of Springfield, before using his new position to antagonize the Simpson family. Fittingly, Bart and Lisa's plan to expose Bob's electoral fraud involves framing Barlow for it.
  • Season 7's "King-Size Homer": Homer has deliberately become hyper-obese, to allow him to work from home and avoid the plant's new exercise program. One day he leaves his remote terminal to try and go to the movies, and by the time he gets back, a meltdown is imminent. Homer tries to warn the plant via phonecall, but discovers that his fingers are now too thick to allow him to use the phone.
    You'd Expect: Homer to grab an object with a small surface area on one side - such as a kitchen utensil - and use it to dial the plant's number, allowing him to warn the plant about the disaster with minimal effort.
    Instead: Homer chooses to go to the plant and manually shut down the system. He only narrowly makes it, and his huge bulk - while ultimately stopping the meltdown - gets in his way a number of times.
  • Season 7's “Homer the Smithers”: Smithers has made a plan to win back his job. It involves calling Mr. Burns’ mother (whom Mr. Burns hates) and transferring the call to Mr. Burns, so Smithers can stop it.
    You’d Expect: Smithers to do it himself because he is capable.
    Instead: He gets Homer to do it.
    Now: Homer has the phone with Mrs. Burns on the line.
    You’d Expect: Homer to press the “Transfer” button because of how obvious it is.
    Instead: He presses the “Disconnect” button, terminating the call.
    Now: Homer poorly impersonates Mrs. Burns, and Mr. Burns finds out about Smithers’ plan, so Smithers is getting a grilling for it.
    You’d Expect: Homer to stand up and admit his role in the plan, and that he did it wrong.
    Instead: “You really blew it this time, Smithers.”
  • In Season 8, "Lisa's Date with Density" features a subplot involving Homer engaging in tele-panhandling using an auto-dialler. Several examples of stupidity abound:
    First: One of the Springfield residents that falls for Homer's "Happy Dude" scam is Abe.
    You'd expect: For Abe to recognize his own son's voice and to either hang up or call his son and ask why Homer is asking people for money.
    Instead: Abe (along with Jasper, who also knows Homer) sends money. He doesn't feel any happier, however.
    • Late one evening, Homer has left the auto-dialler on to call residents who weren't home before, hung up or hadn't been called yet. The calls continue into the early morning hours, and it disturbs many people from their sleep… including Ned Flanders, who repeatedly gets up to answer the phone, thinking it's his mother.
      You'd expect: Ned to either unplug the phone or—knowing Homer's voice, since he has listened to enough of the message to decipher who it is—to go to the Simpsons' residence and request that Homer stop calling.
      Instead: Ned keeps the phone plugged in, certain that his mother may be trying to call him. Even better: Homer doesn't seem to get that the reason Ned's telephone (and his complaining) is disturbing the peace is probably because of his auto-dialler calling the Flanders' residence repeatedly.
    • In the final act, when Chief Wiggum cited Homer for his telemarketing fraud.
      You'd expect: A competent cop to do the same thing Wiggum did with Jimmy the Scumbag, the machine's previous owner: arrest him for fraud and, having obtained a warrant, seize the auto-dialler.
      Instead: Uh boy—what police incompetence here. First, neither Wiggum nor any of the other officers took the auto-dialler with them (for evidence) when Jimmy got arrested; instead, the auto-dialler is kept in the trash, allowing Homer to take it for his own scheme. Later, when Homer is charged with the same crime, Wiggum (1) shoots the machine (causing damage to evidence); (2) fails to take Homer into custody; and (3) (and most glaringly) tells him to bring the auto-dialler with him on his court date. "Otherwise, I got no case, and you go scot-free, you know," says Wiggum rather sheepishly.
    • Homer's court date, where…
      You'd expect: Homer having destroyed the evidence (since he was allowed to keep his auto-dialler), or at the very least erase the "Happy Dude" message.
      Instead: Homer apparently brought it to court—unseen in this episode—because he is ordered by the judge (who apparently has let him off easy) to record a new message apologizing to Springfield residents. Once he says, "I'm sorry" (in an apologetic tone), he then asks for more money through his new "Sorry Dude" scam.
  • "Homer's Enemy," from Season 8 — The entire premise is a "What an Idiot" trope as seen from the eyes of a newcomer employee, Frank Grimes, and his encounters with Homer. Repeatedly, Grimes tries to point out to Mr. Burns and others that Homer is a poor employee, ill-suited to the job and that his lack of qualifications, skills, ethics and attention to the job make him not only a danger to himself and his fellow employees but to Springfield (and possibly a wider region). Many situations abound:
    Early on: Homer is at his work console when he absent mindedly grabs a flask of radioactive acid and brings the lip up to his mouth, as if to drink it. Grimes is walking by, sees what is about to happen, and slaps it away; the substance spills onto the wall, causing it to become damaged, just as Mr. Burns is making his rounds.
    You'd Expect: Burns — who has supposedly hired Grimes for his skills and accomplishments — to realize that Homer was about to drink a radioactive liquid, which would possibly seriously sicken or kill him; also, for Burns to finally realize that Homer is incompetent and to fire him.
    You'd Also Expect: Burns to reward Grimes for saving Homer's life.
    Instead of recognizing Homer's incompetence, Burns is more concerned with the damage to the wall. He reprimands Grimes, demotes him and docks his pay.
    To be Fair Homer realises that he was being a dick towards Grimes, and tried to make amends by inviting him to a dinner in his house, apologise for his idiocy and ask for a second change
    You'd Expect: Grimes realizes that Homer, for all his faults, is a decent man at the core, and after the dinner, tries to reason with Homer by instructing him over what he should do and how to do his job, or more realistically, convince Homer to quit his job for the safety of all Springfield (including his family), or whatever, act like an adult and resolve his feud with Homer.
    You might even expect that if Grimes still feels uncomfortable around Homer then maybe Grimes himself would just resign from the power plant and get a different job.
    Instead: Grimes gets jealous over Homer's (relatively) luxurious life and only increases his anger towards him, and walks away in disgust.
    At same time: A jealous Grimes venting at Homer that he doesn't deserve any of his successes in front of his wife and kids.
    You'd Expect: Marge and the kids would defend Homer that he's only sharing his happiness with Grimes and call out on him for his jealousy.
    Instead: They just stood there and did nothing!
    Later: Grimes vents to Lenny and Carl.
    You'd Expect: For Lenny and Carl to concede that Homer, indeed, is a poor employee who has no business working at the facility.
    Instead: They tell Grimes to lighten up.
    In response: Grimes schemes to publicly expose Homer as a fraud by having him enter a nuclear power plant design contest ... for children (doing so by giving him a flyer that has all of the references to it being a children's contest deleted).
    You'd Expect: Homer to be suspicious, as he had seen the flyer at work and would be able to tell enough about the flyer he received to deduce that it is a contest he is ineligible for. Or, in the very least, for Burns or Mr. Smithers to catch Grimes in the act of his scheme and stop him.
    Instead: Homer takes the bait. (Note that Bart, who also is undoubtedly aware of the contest, also does not point this out to Homer.)
    On contest day: The contestants bring in their models to be judged ... along with Homer.
    You'd Expect: For Burns, who is a contest judge, to immediately realize that Homer is not a child and disqualify him. Or in the very least, for Burns to instantly recognize the other children's models as superior to Homer's simplistic design. (Although Homer showed more technical expertise (for him) in describing how his model works.)
    Instead: Homer is praised by Mr. Burns, before the others agree and applaud him. Homer wins first place.
    The end result causes Grimes to snap and run amok through the plant, complaining that Homer gets away with everything and wins everything, but he (Grimes) has nothing to show for his hard work and superior ethic and skills. At one point, he sees some high-voltage electric wires.
    You'd Expect: Even in his blind rage, for Grimes to at least show reason and know that touching the wires will result in electrocution and possible death.
    Instead: "Well, I don't need safety gloves because I'm Homer Simp—" ZAP!cut to Grimes' funeral
  • Miracle on Evergreen Terrace: at the beginning of the episode, Bart uses the "old Indian trick" (drinking water before bed) so he can look at his presents early. He ends up accidentally burning down the Christmas tree and the presents, so he takes the evidence to the backyard and buries it the snow. By the time he's finished, it's 7:01 a.m., and the family finds the tree "missing".
    You'd Expect: Bart to tell them the truth. It's not like he can hide what happened: someone's bound to find the tree somehow in the next few days (they do), and even if they don't, the snow will eventually melt.
    Instead: He generates a story about how a burglar stole the tree and all of the presents. Way to go, Bart, ultimately making the whole town think that your family scammed them later in the episode.
  • In "Marge Simpson in Screaming Yellow Honkers" from Season 10, Superintendent Chalmers and Principal Skinner, in an act for the Springfield Elementary School talent show, are about to perform Who's on First?.
    You'd Expect: The act to be performed properly, as it had obviously been rehearsed. And nether of the two to explain the joke.
    Instead: Skinner botches the joke by explaining that it's not a question that Chalmers is asking, "but rather a player with the unlikely name of 'Who' is on first." Chalmers lampshades this by answering disgustedly, "Six seconds into our routine and you blew it."
  • In "The Old Man and the C Student," Lisa's letter to the International Olympic Committee gets Springfield the next Olympics. The town greets them at a ceremony in Springfield Elementary, which includes a comedy show by Bart. Principal Skinner got a preview of the act during rehearsals ... and it's an un-pc routine with jabs at the IOC reps' countries.
    You'd Expect: Principal Skinner to get Bart to rewrite the act with good, clean material. Or to not let him perform at all.
    Instead: He allows the act to proceed unaltered. This naturally offends the IOC, who promptly strip Springfield of the Games and award them to Shelbyville. Skinner promptly assigns the entire student body 20 hours of community service just to save face.
  • In the season 11 premiere "Beyond Blunderdome", special guest star Mel Gibson has mounted a remake of the Jimmy Stewart classic Mr. Smith Goes To Washington. Despite getting a positive response from test audiences and the assurance of the producers that he's got a hit on his hands, Mel can't shake the feeling that something's wrong with the film, believing that the test audiences like him too much to give him honest criticism. He then reads a very negative review from Homer, who was part of the test audience as a prize he won but is angry that it wasn't the prize he wanted, and because Mel was flirting with Marge earlier.
    You'd expect: Mel would dismiss the ridiculous letter for the absurd and totally misplaced piece of anger that it is, or that he would listen to the producers who tell him that it's a load of nonsense.
    Instead: Mel thinks that Homer is literally the "one guy with the guts to tell [me] the truth", tracks Homer down and asks him to be a consultant on the film, which leads to Mel retooling the ending of the film to replace the original impassioned speech about liberty with an ultra-violent and bloody climax at the advice of Homer, despite the producers trying to warn him that he's destroying his own film.
    Result: Homer and Mel's actions lead to a very bad reaction from audiences when the film is released months later with the new ending and Mel is completely surprised to find that audiences - especially the Springfield residents who served as the film's test audience - hate it. He even ends with Mel getting hit with a defamation lawsuit from Jimmy Stewart's own daughter. In the end, at least Mel finally realizes that Homer really is just a stupid jerk and not the one honest critic he thought he was and angrily kicks Homer out of his limo when Homer tries to give him career advice on how to bounce back from the fiasco (Homer even suggests that Mel do an Indiana Jones film, despite that franchise being headlined by Harrison Ford).
  • In the Season 11 episode "Guess Who's Coming To Criticize Dinner," Homer prepares to eat an éclair laced with poison. Lisa shouts that Homer is about to ingest something highly toxic.
    You'd Expect: Homer to throw the éclair away.
    Instead: Homer still tries to eat the éclair, declaring that he's had a good life (only to toss it when Lisa tells him it's low-fat).
  • In "Missionary: Impossible" from Season 11, when Homer goes overseas to engage in a missionary trip, Bart has taken over the position of "man of the house" and takes over his father's job at the Springfield Nuclear Power Plant. Mr. Burns storms into Homer's workstation to reprimand him for years of poor performance.
    You'd Expect: Mr. Burns—even with his advanced age and declined mental acuity—to recognize that whom he is about to scold is not Homer, given that Burns and Bart have encountered each other numerous times.
    Instead: Mr. Burns yells at "Homer" anyway, even as Bart tries to explain that he is not Homer.
    However: One of the running gags in the show is that Burns doesn't recognize or remember Homer no matter how many times they cross each other's paths. Either due to senility or because he just doesn't care. It's not as if Burns would be above child labor either.
  • In Season 12's Day Of The Jackanapes, Sideshow Bob brainwashes Bart to help him kill Krusty by rigging himself with plastic explosives. In order to train him for this task, he has Bart destroy a statue of Krusty outside the Krusty Burger. Incidentally, Chief Wiggum is right outside and notices what Bart and Sideshow Bob are doing.
    • You'd Expect: Chief Wiggum to notice that something is up (Bart is Krusty's biggest fan ever) and get suspicious of Sideshow Bob.
    • You'd Also Expect: Chief Wiggum to apprehend Sideshow Bob and Bart for vandalism.
    • Instead: Chief Wiggum notes that that he's glad that Bart is having fun.
  • In Season 13's "Homer the Moe," Bart calls Moe's when Homer is substitute bartending.
    You'd Expect: Homer to play along with the joke.
    Instead: Homer totally screws things up, not knowing what he's supposed to do. (Although one interpretation is that Homer was cleverly thwarting Bart through his playing dumb).
  • In the Season 16 episode, "On a Clear Day, I Can't See My Sister", Lisa files a 20-foot restraining order against Bart, which she quickly abuses as payback for all the stuff Bart did to her. Him and Marge go to Judge Constance Harm to try and get the order repealed.
    You'd expect: Have the two calmly discuss with Harm what's going on and maybe she'll have the order repealed or Bart can tell Judge Harm that Lisa (the one who put the restraining order out on him in the first place) is harassing him, which, if you know anything about how restraining orders work, is grounds for having it repealed.
    Instead: Bart makes wisecracks at Harm's marriage life (apparently forgetting that he had to put up with her attitude in a previous episode), which causes her to extend the order to 200 feet.
  • In "Future-Drama" from the same season, Lisa in the future-projection starts dating Milhouse when he saved her from a fire. That she later finds out he started. Frink even shows Lisa's reaction where she's clearly much younger than in the rest of the simulation.
    You'd expext: Lisa immediately dumps Milhouse like a sack of bricks and likely turns him in for arson.
    Instead: She continues to date him for years after finding out. And no, it's not why she eventually breaks up with him. Milhouse basically pulled an idiotic stunt that could have gotten Lisa killed just to get into her pants and it worked! How is she even graduating at all if she's that stupid?
  • In Season 17 "The Monkey Suit", Ned Flanders and Reverend Lovejoy blackmail Seymour Skinner into teaching creationism at Springfield Elementary School. Lisa brings this up at a town meeting.
    You'd expect: for Lisa to point out that creationism is not science, that it makes no sense to teach it at normal school when it is already taught at Sunday school or even that it is unconstitutional (as it would mean a public (government-sponsored) school favoring one or more religions against others, something that goes against the First Amendment).
    Instead: she just asks people to vote on choosing between creationism and evolution. Naturally, the people of Springfield choose the former, and it is soon forbidden to teach the theory of evolution at all.
  • Season 18's "Revenge is a Dish Best Served Three Times" has Homer seeking revenge on the Rich Texan for cutting him off. His wife and kids try to stop him by telling him stories that discourage revenge, starting with Marge's story of the Count of Monte Cristo. Turns out Homer was jamming to Jamacan beats and misses out on the whole story.
    You'd Expect: Marge to hold her tongue. At least this way, he's too distracted to think about revenge.
    Instead: "Weren't you listening? I just told you a whole story about revenge!" This reminds Homer that he has revenge to carry out.
  • In Season 20's "Homer and Lisa Exchange Cross Words," Homer makes a bet against Lisa, his own daughter, in a crossword puzzle tournament. Homer ends up winning the bet, gaining a huge load of money.
    You'd Expect: That Homer keeps the whole thing hidden (like keep most of the winnings in a bank or something) so no one would suspect a thing.
    Instead: He buys and shows off a lot of new expensive things that make it clear to everyone that something's up. This allows Lisa to get Homer to confess that he bet against her, then Lisa ends up disowning Homer as her father.
  • In the subplot of the 20th season episode "The Good, the Sad and the Drugly," Lisa looks up a website for a school project that covers what Springfield will be like 50 years in the future, and it says a Bad Future is in store.
    You'd Expect: Lisa to give it some deep thought and disregard the website as fraudulent (or a spoof a la The Onion), since the predictions it makes are too absurd and apocalyptic to have any basis in fact.
    Instead: She believes everything the website says, hook, line, and sinker.
  • In Season 20 episode "Gone Maggie Gone," Maggie is proven to be the solution to world peace, provided she lives in a nunnery.
    You'd Expect: Marge to do the mature thing and allow her child to stay there, since a nunnery isn't that bad of a place to be. Plus, small price to pay for world peace, right?
    Besides: Nobody said that Marge (and the rest of the family by extension) couldn't live in the monastery as well, if she wanted to be with Maggie, right?
    Instead: Marge goes all "She's mine and no one else's" and keeps her. No explanation beyond "God would never ask anyone to give up their child for the good of the world" is given. This is fairly annoying since she learns that her children have to leave their nest in almost every episode about her. A MAJOR Flanderization of her Mama Bear attitude to be sure.
    Bonus Points: Homer somehow comes to the conclusion that Bart could qualify for a Replacement Goldfish. Cue to the entire church becoming hell.
  • In "No Loan Again, Naturally" from Season 20, Homer and Marge are in a state of depression due to longer being able to afford their mortgage payment. Homer especially, since he is Driven to Suicide and planning to hang himself from a tree outside the house. Bart and Lisa are there to witness it.
    You'd expect: Bart and Lisa to stop Homer from going through with it.
    Instead: They just stand there and watch him hang himself. Granted, the tree falls over from Homer's weight, but still...
  • In "Lost Verizon" from Season 20, Bart gets a mobile phone, and Marge (under advice of Denis Leary, the phone's owner) activates its GPS tracker, allowing her to keep track of Bart and stopping him from doing anything she doesn't like. Lisa tells Bart what has been going on, and Bart manages to take the tracker out and tie it to a bird. Suddenly, Marge begins to see Bart moving at high speeds.
    You'd Expect: Marge to figure out that Bart has found the tracker.
    Instead: She thinks Bart is running away and proceeds to take Homer, Lisa and Maggie on a road trip... to Peru.
    • Also, when they are mid-trip, Lisa sees the bird Bart tied the tracker to, and finds out that it is from a species that migrates to Machu Picchu, a place she wants to visit.
      You'd Expect: Her to warn her parents, given the high expense of traveling to Peru - which Marge had mentioned earlier in the episode.
      Instead: She waves the bird away.
  • Season 21's "The Bob Next Door". It is revealed late in the episode that Sideshow Bob has surgically swapped faces with his prison cellmate, Walt Warren, in order to get himself released in Walt's place. Walt realises that Bob is going after Bart again and attempts to warn the authories, but the transplant has left him unable to speak properly, resulting in him getting put in a straitjacket and shut in a padded cell. He resorts to repeatedly writing his warning on the wall of his cell.
    You'd Expect: Walt would write something like "Sideshow Bob has escaped" or "Sideshow Bob has my face", or anything else that explains clearly what's happened.
    Instead: He writes "Bart Simpson will die". Predictably it gets mistaken for a threat on Bart's life, and Walt has to resort to breaking himself out to save Bart. Marge lampshades this:
    Marge: "You have to admit, "Bart Simpson Will Die" was kinda open to interpretation."
    Walt: "I'm not a writer."
  • In Season 24's Treehouse of Horror story parodying Paranormal Activity, the family finds out that the house is being haunted by a winged demon who looks like Moe that was summoned years ago by Marge's sisters and is taking Maggie as part of Marge's deal to spare her sisters.
    You'd Expect: Homer to sic the demon on Patty and Selma, since they were the ones who summoned the demon who was tormenting the family (plus, they lied when they said that if Marge spared them from the demon that they would never make fun of any man Marge dated or married).
    Instead: Homer is forced into three-way sex with two demons and Patty and Selma get away scot-free.
  • In the Season 25 episode, "The Man Who Grew Too Much," Lisa finds out the person who tried to kill the Simpsons, Sideshow Bob, is actually cultured and knows famous poets, authors, and artists. Bob asks Lisa to visit him again, calling her the best Simpson out of the cesspool.
    You'd expect: Lisa to completely reject it, or refuse politely, or visit with a bit of suspicion since this is the same person who tried to kill her family. Who knows, Bob might try to go crazy and try to kill them again.
    Instead: She says someone with a cultured mind and brain can't be evil. And she even said "He only tried to kill Bart." Ignoring the fact that in some episodes, Bob was trying to kill all of the Simpsons. Sure, Lisa does ask what his plan is and doesn't care until she sees her new "friend" lift an art piece that is supposed to be too heavy to lift alone. She later finds out what was his real plan, and surprise surprise, Bob tries to kill Bart and Lisa again.
http://tvtropes.org/pmwiki/pmwiki.php/WhatAnIdiot/TheSimpsons