Say a character finds out about a paranormal phenomenon, or a sinister conspiracy. There wouldn't be much of a plot left if they could just call the police and let them take care of it.
In these cases, heroes will simply talk like stereotypical portrayals of paranoid schizophrenics.
They will continually repeat a bizarre claim in a panicked voice.
They will avoid mentioning what led them to believe it in the first place.
They will never consider sticking to the provable parts of the story for the time being.
Most important, they will be stunned and angry that anyone would find their claim implausible, regardless of how implausible it would be even if they weren't completely flushing any credibility they might otherwise have down the toilet in their method of persuasion.
In extreme cases, they may respond to skepticism by wondering out loud if the disbeliever is "in on it." And if anyone tries to calm them down, rather than taking a few deep breaths, sitting down for a moment and coming back to the problem in a calmer fashion they will immediately violently lash out, thus prompting the immediate summoning of the nearest security guards to have them ejected from the premises.
Averted and Lampshaded when Pai has been locked inside a club with demonic marionettes with her two friends Dee and Ken-Ken stuck outside. When Dee suggests they call the cops, Ken-Ken mentions this trope by sarcastically saying the cops would give them a drug test if they said things that crazy. Dee then says that they should obviously leave the parts about the dolls out and just say their friend was trapped inside a skeevy club... which is partially true and something a cop should listen to.
A segment in House of Mystery #227 called The Weird World of Anton Borka, a young farmer is Blessed with Suck via a gift from an old peddler. Anton's able to see a group of strange creatures who promise to ensure he has good fortune, but because only he can see them the rest of his town think Anton's insane. No matter how much he pleads that the creatures are real everyone just shrugs it off as "crazy Anton".
In Runaways, the kids call the Avengers hotline to report their parents (who are villains). The operator says they always get calls like that around report-card time, and dismisses it. The guy who made the phone call was actually The Mole. Of course he's going to make it sound outrageous. Having the group get actual help is the last thing he wants!
In Fever Dreams when L is sick he begins raving to everyone that Light is Kira and he's going to kill us all! Everyone attributes it to L's high fever. It doesn't help that in his fever and paranoia L assumes that the doctor Watari brought in must be in on the conspiracy. L was right and Light is up to something but for once it doesn't involve killing anyone.
In A Very Potter Sequel, when Harry asks the guard how to get to platform nine and three quarters, the guard insists that it doesn't exist. Harry uses the trope nearly by name, and starts talking about his Hogwarts letter. When the guard starts to walk off, he yells, "Sir! Listen, please! A bird gave it to me!"
Invoked from the flip side as well when the guard says that hundreds of kids have asked him the same question that day, and he refuses to believe it exists or there's anything worth looking into.
The movie Chicken Little uses this one a lot. Chicken Little's flabbergasted babbling as he attempts to explain himself isn't exactly helped by his own father apologizing for his craziness to the townspeople.
Appears in Mulan, as she struggles to tell her former teammates that some of the Huns have survived an avalanche that buried their army.
In Recess: School's Out, three different groups of people report strange happenings in Third Street School: TJ reports the green laser, his friends report his kidnapping, and even the typically unhelpful Ms. Finster reports ninjas. And yet, the cops make no connection and just laugh each one out of the room.
Films — Live-Action
The hero of Shock Corridor had himself declared insane and sent to the asylum, where he eventually fails to convince the shrink of his sanity.
This is ridiculously common in slasher and monster flicks where the hero(es) have to warn the general public of the impending danger.
In The Amazing Spider-Man, Peter tries to convince Captain Stacy that Dr. Connors is the Lizard with nothing but his say-so to back it up. Stacy has him removed but does ask one of his officers to look into it.
Somewhat reversed in An American Werewolf in London, as it's one of the walking corpses who's trying to convince the living protagonist, who dismisses them as a hallucination.
"Goddammit, David, please believe me! You'll kill and make others like me! I'm not having a nice time here."
In Beware! The Blob!, the female lead witnesses the eponymous monster's first two victims, then almost becomes a victim herself. When it comes time to alert the public, the most coherent thing she can utter is "It came after us; it came after us!" She does get a little better by the end of the film; but by this time, as per the dictates of the trope, her credibility is done gone shot.
In The Cabinet of Dr. Caligari, Frances suspects that Caligari and Cesare are responsible for the murder of Allan, a point he argues very poorly to the police, although justified because he's batshit insane.
The eponymous character in Coraline attempts to contact the police and explain that her parents were kidnapped, but once she gets to the part about the Other Mother, they shrug it off. Admittedly, she could have at least convinced them that her parents really were missing, but that doesn't mean they could do anything constructive. She also tells Wybie what's going on, but she doesn't try very hard to convince him, and is more venting at him than trying to explain anything. (Also somewhat justified by Wybie being rather a smart-arse.)
Basically the entire plot of A Cry in the Wilderness, in which a father, suspecting that he might have contracted rabies, chains himself up in a barn, telling his son not to release him under any circumstances. Later he realizes that there is an imminent flood.
A review of Evan Almighty posed the question that never seems to be answered in those kinds of movies — so Steve Carell tells his wife he's been chosen by God to recreate the Noah story and that's why all this weird stuff is happening. She doesn't believe him. Why doesn't he take her into the bathroom and show her how his beard grows back immediately when he shaves it, and so on? (Of course, the movie as it is depends on characters assuming that everything that happens to Evan is some kind of misguided attempt at humor he's engineered and is now refusing to let go, no matter how miserable it clearly makes him and how much he insists that it's not his fault.)
Given the idea behind Evan Almighty, in that case it's probably done as a point about the Christian concept of faith, which is to be expected of believers without the demand of proof.
Early in the Friday the 13th series, "Crazy Ralph", a local vagabond, would show up to try to warn people to stay away from Crystal Lake. In the end, the only person to take him seriously is Jason Vorhees, who cuts Ralph's throat early on in Part II.
Played with in the original Fright Night, when Charlie, convinced that his neighbor is a vampire who has been murdering local women, only tries to convince the police that his neighbor is a murderer, rather than a vampire. Sadly, when he doesn't have enough evidence, he goes right to the vampire story.
In Galaxy Quest, Jason Nesmith tries to tell his co-stars that the odd-looking fans at the convention were really aliens: "They were termites... or dalmatians!" They don't believe him at first, even when a couple of the Thermians (shapeshifted into humans) arrive.
Speaking of Gremlins, this is what happens when the hero tries to explain the title creatures to the cops. And again in the sequel.
Happens a lot to Nora in House on Haunted Hill (1959), who keeps seeing dead bodies and blood stains. It's part of an elaborate plot to keep her constantly on the verge of a nervous breakdown. By the time her Implied Love Interest, Lance, eventually spots one of the severed heads she told everyone about, he's had it with this trope, so he grabs the head by the hair and takes it to show everyone.
The original ending of the 1956 Invasion of the Body Snatchers defines this trope, when the main character runs down the highway hysterically screaming at passing motorists that "They're here! You're all next!". The aliens even let him go, pointing out that no one's going to believe him anyway (and especially not if he's acting as hysterically as that). However, the studio was not satisfiedending on such a dark note, and added a Framing Device of the hero in a hospital telling his story to a pair of FBI agents, who don't believe him either... until a passing orderly mentions a car accident involving a truck full of strange, vegetable-like pods.
Generally averted in The Midnight Meat Train, where the protagonist (played by Bradley Cooper) is quite reasonable and diplomatic with the police detective, accepting that the evidence he has is not enough to convict Vinnie Jones of being a Serial Killer. Unfortunately, his paranoiac dedication to finding out the truth drives him crazy.
In The Mist, David Drayton makes a very lame attempt to tell Norton about "the creatures in the mist". Even his companions comment this to themselves.
Played with in Small Soldiers. The main heroine is trying to call the police to help them against the attacking toys, and insists that it's not a prank call. Then she reverses herself and says that it is, "So you'll come over and arrest me, right?" They hang up.
Subverted in Star Trek; when he's figured out what's going on, Kirk races into the bridge like a madman yelling about how it's a trap. Given his actions — plus the fact that he's pretty much a stowaway — Captain Pike is within seconds of having him locked up when Uhura validates Kirk's story with evidence and Spock (who has been given no reason to like Kirk) acknowledges both that Kirk's theory is logical, and Uhura's linguistic skills are beyond reproach. This plus the fact that Pike wrote his dissertation on the anomalous event Kirk is trying to prove is happening a second time, and Pike gives Kirk the benefit of the doubt. It also helped that Kirk was acting fairly calm and rational, at least compared to most people described on this page.
At first the main character of Take Shelter tries to hide his fears because he knows everyone will assume he's crazy. Eventually, though, he has a full-blown outburst at a work event, resulting in the page quote.
In the first few minutes of the 1982 version of The Thing (1982), some Norwegians land their helicopter near the American base and start shooting at (what looks like) a Siberian Husky. When some of the Americans come out to see what all the fuss is about (including the security guy with his revolver), instead of dropping their guns and de-escalating things, the Norwegians keep excitedly shouting (in their native tongue) and shooting at the dog. The security guy pops them both before they can tell the Americans about the dog-thing.
The Whole Nine Yards: Sophie says this to the police when she's being interrogated about hiring a hit man to kill her husband. Which she did. But he didn't kill him, because Nicholas faked his death.
In the sixth Harry Potter book, Harry is suspicious about Draco but unable to keep his calm about the matter, and even his best friends suspect that he's not being entirely sane about the whole thing.
Aside from Dumbledore and Sirius, everyone always seems to disregard Harry's theories almost offhand:
In the first book, nobody wanted to hear that he thought the Philosopher's Stone was being stolen.
In the third, nobody listened when he claimed Sirius was innocent and Peter Pettigrew was still alive.
He spends most of the fifth trying to convince the world Voldemort was back.
And in the sixth nobody, including his personal friends, believe him when he says Malfoy is a Death-Eater. This does have an instance of Crying Wolf and people do take him seriously at times (like when Mr. Weasley is attacked), but by the end of the sixth book, when Professor McGonagall is point-blank asking him for his input on something, he keeps it a secret, having apparently decided Adults Are Useless.
In the book of Freaky Friday, the protagonist starts, well, freaking out for a variety of reasons, one of which being that while she is inhabiting her mother's body, her mother has presumably gone joyriding in hers, and is now nowhere to be found. She decides to call the police. Instead of saying, "I'm deeply concerned that my daughter has vanished", she decides to blurt out the whole body-swapping story. The cops, unsurprisingly, think she's nuts.
In A Song of Ice and Fire, Arya overhears a pair of people discussing their massive gambit. However, with most of the discussion going completely over her head, what she does remember of it when she tells her father sounds completely nuts, even though her father is currently investigating part of said gambit. Except it's not, actually, she just thought it was and presented it to him as such, so he was perhaps right to ignore her (the discussed gambit hasn't actually impacted the plot... yet), if for the wrong reasons.
Brienne combines being a very bad liar with a habit of getting into hard to believe situations, with the result that she tries to tell the truth but it comes across as an incredibly feeble lie. Most simply she had this story: "I didn't kill him! A magical shadow came out of nowhere while we were alone and cut his throat!"
Near the end of The Sharing Knife: Horizon, while Dag has, admittedly, had a pretty rough night, and just about anyone would be forgiven a fair bit of hysteria over finding their spouse Buried Alive; an authoritative explanation about the Enchanted Lakewalker Wedding Cords would have gotten Fawn dug up far faster than clawing at her grave barehanded while screaming "She's not dead! She can't be dead!"
Averted in the Darkest Powers series by the main character, Chloe. In the first book, she's sent to a group home, where she's diagnosed (incorrectly) as a schizophrenic — she's actually a necromancer. After realizing that she and the other kids are in danger, and then escaping and being chased down by the staff with tranquilizer guns, Chloe manages to get to her Aunt Lauren's house. Once there, she immediately tells Lauren about being hunted down by the staff. But rather than blurt out the entire insane story to Lauren, Chloe leaves out the part where she's a necromancer, ghosts are real, she accidentally raised the dead, and the people she was fleeing with include a fire half-demon, a sorcerer, and a werewolf. And, in an even further aversion, before going to her aunt, Chloe actually takes the time to go back to the scene to bring evidence in the form of a tranquilizer dart, because she knows that she'll be just brushed off as crazy otherwise. So it's a damn shame that all of this effort goes to waste when it turns out that her aunt knew about everything all along, and was, in fact, in on the whole plot.
Happens often in Goosebumps books—in fact, one of the short stories in the collection More Tales to Give You Goosebumps is actually titled "You Gotta Believe Me!".
"He met a wagoner and tried to make him understand, but the tale he told and his appearance were so wild—his hat had fallen off in the pit—that the man simply drove on."
Hoffmann from The Fear Index increasingly sounds like this as the events of the book unfolds. What first throws his sanity into question is when he insists a picture in a 100 year old book is a clue to the break-in of his house. Amazingly Quarry still believes him, but only because Hoffmann was never that normal to begin with.
The first Galaxy of Fear book has no one believing that people are disappearing in the middle of the day, because the man who sees it is considered mad and they don't even see the extra footprints in the bare earth. He actually fetches his one remaining crewmember from her safe place with the idea that people are more likely to believe her, and when shedisappears he hits his Despair Event Horizon.
In a later book a hacker warns Zak that the ship's computer, which Zak is trying to give full control of the ship to, is evil. Of course, he'd self-sabotaged there - in their previous interaction the hacker had agreed to let Zak examine some of the ship's functions, then immediately shut them down and blamed Zak for the failure. The hacker was also highly disheveled from being tortured by the computer, and the safeguards built into computers and droids to keep them from spontaneously becoming evil are so ingrained in popular consciousness that the idea seems laughable to Zak.
Sort-of subverted in the Buffy the Vampire Slayer episode "Bad Girls" from the third season. After Faith accidentally kills a man, Buffy agonizes over what to do for deciding to tell Giles... only to find Faith has beaten her to it and blames it on Buffy. When Faith is gone, she pleads with Giles to believe the truth... and finds he does quite unequivocally, Faith having "many talents" but lying not being one of them. He also notes almost casually that Slayers killing innocents by accident certainly isn't unheard of, and that it's dealt with internally by the Watcher's Council.
Which leads to a rather sad and long case of Poor Communication Kills with Faith as she becomes so closed off about it and paranoid that when she hears the rest of the gang talk about how they're going to "deal with her" she assumes the worst while in truth they are probably considering hiring a therapist and contacting the Council to do a clean up job.
Sort-of subverted again the fourth-season "Who Are You?" when Faith switches bodies with Buffy. Buffy is quite able to convince Giles that it's her by rattling off a string of rather embarrassing facts about their relationship that Faith couldn't know.
Buffy-in-Faith: Giles, you turned into a demon and I knew it was you! I mean, can't you just look in my eyes and be all intuitive?
Giles:(suddenly interested) How did I turn into a demon?
Buffy-in-Faith: Oh! 'cause, uh... Ethan Rayne! And-and you have a girlfriend named Olivia, and you haven't had a job since we blew up the school... (beat) ...which is valid, lifestyle-wise. (Giles is abashed) I mean, it's not like you're a slacker type or - Oh, oh! When I had psychic power, I heard my mom think that you were like a stevedore during sex. Wh- Do you want me to continue?
Giles: Actually, I beg you to stop.
Buffy-in-Faith: What's a stevedore?note A type of dock worker who unloads boat merchandise
Played straight, if fairly subtly, in both Buffy the Vampire Slayer and Angel: If Angel wants someone to invite him into their home so he can protect them, he won't say "May I come in?"; he will instead demand that they invite him in. This makes him sound like a crazy person. They never do. In Angel this causes the death of Kate's father.
Another Buffy example: In the episode The Pack, Giles refuses to believe Buffy when she claims Xander has been possessed by a hyena spirit. Being Buffy, she calls him on it:
One episode has the monster of the week split Xander up into two separate beings, one having his strong traits and the other with his weak ones. Weak Xander believes he is the "real" Xander, and tells Willow there is an imposter and recounts things from their childhood and does the Snoopy Dance (which is completely adorable). It turns out to be unnecessary, as Willow quickly figures out what is going on.
In The Outer Limits episode "The Special One", a father asks the board of education if they provide tutors as part of the enrichment program. When he's told that they don't, he reveals that a man posing as a tutor has been visiting his son. And then he reveals that the man isn't human, is from outer space (which he couldn't possibly know), disappears and materializes, and then starts talking about climate control machines.
Mulder of The X-Files has a bad habit of this; when trying to enlist outside aid in dealing with a case (local police, FBI higher-ups, etc.) he makes sure to tell them exactly what he thinks is going on, no matter how insane, as opposed to sticking to the parts they're likely to believe.
This becomes almost something of a Running Gag, since no matter how crazy the theory and how much Scully cites scientific research that he's wrong, Mulder is always right.
As well, some of The Men in Black are pretty Genre Savvy about this, deliberately acting as strangely as possible and using agents who look like famous people (or perhaps even making an agent, say, the host of a game show), so that anyone who tries to tell other people about them won't be believed.
In the episode Synchrony, an elderly man (who's actually from the future) approaches two guys and starts a rant about how one of them will die in a traffic accident while crossing the street that evening, and how this must not happen. Of course, they don't believe him. If he'd calmly started a conversation with them and held them up for just a few minutes, he'd have easily succeeded.
Played with in the first episode of the 2005 series of Doctor Who, when Rose meets with a conspiracy theorist who has information about the Doctor (whom she has kept mysteriously bumping into). Initially, he starts off presenting his theories about why the Doctor keeps popping up in different parts of history in a calm and reasonable fashion, and presents a relatively plausible theory that she'd be likely to believe — they're all different men who are related and sharing a codename. Then, as he gets a bit carried away with having an audience, he starts getting a bit more worked up and intense, until he's convinced that Rose believes him fully and so blurts out his real theory (which is the truth) — that they're same man, and the Doctor is an alien traveling through time. Unfortunately for him, he hadn't quite won Rose over before this, who leaves believing that he's a nutcase.
One of the Big Finish Doctor Who audio plays, Minuet in Hell, has the Eighth Doctor lose some of his memory after crashing the TARDIS and winds up in a mental hospital. He tries to tell people his name and what happened, and tells the Brigadier when he shows up that he (the Doctor) recognizes him, but no one believes him, because, well, he's in a mental hospital (the Brig doesn't recognize him because he hadn't seen that incarnation before).
Averted in "The Eleventh Hour": The Doctor breaks into a house, and keeps shouting about Prisoner Zero. He is knocked out cold, cut to a hospital. Despite our expectations, he isn't there.
Later played straight in the same episode when the Doctor does beg Amy to "believe for twenty minutes."
The Doctor's pleas to the alliance at the end of The Pandorica Opens.
This is Tru's default state in Tru Calling. When subtler methods of informing people of their own impending death fail or are sabotaged, she always falls back on this line. Not only does it never help, it was likely similar antics from Tru's mother (who had Tru's powers) that got Davis' wife killed, so Tru should really know better.
Subverted in an episode of Stargate SG-1, where after relating a prophetic dream he's had to General Hammond, Dr. Jackson is surprised when Hammond asks what he can do to help. When asked why he believes Jackson, Hammond gets Genre Savvy, alluding to all of the other crazy things he's seen and heard while in command of the SGC.
Also played straight in several episodes. In the three episode arc that ends the first season no one believes that Daniel Jackson had gone to an alternate reality despite the fact that he had evidence in the form of a staff weapon blast on his shoulder and had disappeared for several hours with no other explanation. Later, and more (though not entirely) excusably, he has a hard time convincing people to take his theory about Teal'c's sickness seriously after he apparently develops and then recovers from schizophrenia. The latter is also a massive case of Hollywood Psych.
The same thing later happened to Jonas Quinn. When he starts seeing bugs that no one else can see, Hammond immediately orders a lockdown and a full sweep of the base. Granted, Jonas was the only one to touch the strange alien device, but he was also the only one who'd spent his entire life around a specific type of radiation that's known to cause schizophrenia, so, well...
In one episode, Daniel actually did get driven insane by some alien technology, and as a result was put in a mental hospital. During his stay, the technology leaves him and he recovers his wits. He starts to realize what's happened and tries to explain it... only for the attending doctors to ignore him because, after all, he's crazy.
Daniel: "Why does everyone think I'm crazy!? *beat* Probably because I'm acting like it, aren't I?"
Doctor House from House is a brilliant medical expert who nails the most bizarre diseases and syndromes week after week, yet nobody ever believes him when he dismisses the obvious diagnostics of the other doctors, despite there always being a nagging little detail that derails the simple explanations. Oh, and the standard treatment to the obvious diagnostic always seems to instantly kill the patient if administered before House stops them.
House: IT'S NOT LUPUS!
Then again, it doesn't help his case that he's a sarcastic curmudgeon with a bad case of pain killer addiction...
Plus House himself will usually come up with a completely wrong diagnosis, that nearly kills the patient, before he comes up with the right one.
House: I'm almost always eventually right.
An episode of Season 2 of Amazing Stories is actually titled "You Gotta Believe Me". It involves a man who has a horrific dream of a plane crashing into his house in the middle of the night. As he walks among the wreckage, he sees ghosts of some of the passengers and the ghost of the pilot talking about having to attempt take off too early due to something being on the runway. He wakes up and, while still in pajamas and robe, heads to the airport. While there, he sees the things that were part of the wreckage in his dream (including a girl's Teddy Ruxpin toy) and some of the ghosts. Convinced his dream was a prophecy, he keeps trying to convince the passengers, crew, security and so on that the plane's going to crash and gets more and more frustrated by people not taking him seriously. In the climax, he's on the tarmac and sees a single-engine plane with a drunk pilot taxiing onto the runway, heading into the path of the airliner. He rams the plane with a forklift, saving the passengers. Security grabs him and he says: "They were going to crash! You gotta believe me!" At which point, they finally do.
Happens so, so, so many times in The Time Tunnel. The two protagonists always jump straight to "We're from the future," never bothering to come up with some more plausible explanation for how they know what they do, no matter how many times it doesn't work. Though it is nicely subverted in one episode where Doug confesses everything while being affected by a truth serum, which just causes his captors to think he's been conditioned to resist the serum and consider this proof that he's a professional spy.
A good example of this is "Realm of Fear", in which minor character Barclay, who has a well-deserved reputation as a twitchy, paranoid hypochondriac, spontaneously develops a fear of the transporters, insisting that he's been bitten by something living inside the beam. Picard gives him a long, hard look... then tells Data and Geordi to tear the transporter apart looking for the problem, because he knows that Barclay is fully aware of his reputation, and wouldn't risk the humiliation of reporting to him directly unless he were absolutely positive.
Another episode, "The Wounded," features a starship captain who is convinced the Cardassians are rearming in preparation to break the peace treaty with the Federation. He's right, but unfortunately, instead of amassing evidence and going to his superiors, he proceeds to just start blowing Cardassian ships away left and right and then rants like a lunatic about how "they're all the same" and "I can smell their deceit" when Picard calls him out on it.
The final episode plays with every aspect of the trope, with Picard traveling through 3 time periods. The present crew believe him outright. The future crew has doubts, since future!Picard is suffering from a brain disorder known to cause delusions, but he calls in some favors and they go along out of a sort of familial duty. And in the past, having "just" arrived on the Enterprise, he simply opts to not tell them at all and just starts barking out orders.
Gibbs: Skipper, I have reason to believe a bomb, possibly containing a biological agent, is set to detonate aboard this ship by sunset.
Captain: How real do you think that threat is?
Gibbs: (flatly) Very real.
Captain: (immediately turns around to face the XO)Sound General Quarters. Deploy the flying squad, start with the ventilation systems, and alert sickbay to the situation and have them stand by.
Another notable example is "Enigma", in which Gibbs' old CO enters stage left exemplifying this trope in full, with breathless panicked warnings about a massive black ops conspiracy going to the highest levels of the US government that's illegally manipulating wars, siphoning money out of Iraq, faked the death of Gibbs' old platoon leader to use him as one of their black operatives (before he defected to the colonel's side), and going to kill him. Turns out that the colonel actually is a paranoid schizophrenic, it was all in his head, the 'not really dead' guy is a hallucination only he can see, and the "massive conspiracy" was just a few guys embezzling some money that he stumbled across, and which his insane brain seized on and built up into a massive edifice of paranoia.
The Daily Show: Played for Laughs by Rob Riggle's character, whose often somewhat valid points which are completely overshadowed by his borderline psychotic personality.
Played with in Quatermass II. Professor Quatermass is trying to get a committee of Obstructive Bureaucrats to authorise an inspection of a well-guarded synthetic food factory, which has some connection with strange hollow meteorites landing in the area. A politician who also wants to get to the bottom of the matter agrees to help him, and starts pitching to the committee the idea that the factory might be in danger from these meteorites crashing down on top of it. Rather than realising what he's up to, Quatermass keeps interrupting to 'correct' the politician's supposed scientific error.
Burn Notice: "Burn [Notice] After Reading" has a guy going to Michael claiming that a woman at his workplace is an alien bent on world conquest. While the client is obviously delusional, the woman was actually selling the names of spies, so he was right about there being a conspiracy, it just wasn't the one he thought.
This is also happens to their opponent one week. When Michael finds out about a well connected father who was beating up his wife and kids, he decides to do something about it. The problem is that his brother is a gangster and therefore they have to drive a wedge between them. When they find that the father was doing side deals, they convince him that those deals have caused someone to want to kill him and that he must leave town. Unfortunately, this is when his gangster brother shows up and begins to question him. They then pass of the abusive father as crazy when Michael, Sam and Fiona all appear randomly on the street and the father begins claiming to his brother that he saw the three of them killed.
Get Smart: Events in "The Little Black Book" force Maxwell to tell an old friend of his that he is actually a spy instead of being in the greeting card business. He isn't convinced until Max drags him to CONTROL headquarters (by way of the telephone booth) and has him talk to the president on the cow horn phone.
Firefly: The parents of Simon and River Tam have some excuse for not believing their son when he claims their daughter, supposedly safe at a government school, is being tortured and tries to hire criminals to kidnap her. As it happens, Simon is absolutely right, but it isn't exactly the most believable of stories. A deleted scene implies that they didn't completely disbelieve him either, but were also afraid to go poking around in Alliance business.
Misfits: Nathan yells dramatically at his mother that her boyfriend is a "psycho, rough-trade, gay, rapist werewolf!" Granted, his mother probably wouldn't have believed him even if he'd just calmly explained the situation (especially considering that Nathan is pretty much a compulsive liar, and had leapt to a rather silly conclusion based on what he'd seen anyway) but by the time he realized that babbling like a crazy person probably wasn’t doing him any favors, she'd already totally dismissed him.
This is the title character's usual tactic in Merlin. He never has any proof, because obviously A Wizard Did It, and so it never works. You'd think he'd learn after a few tries. Or alternatively, you'd think the other characters would learn that no matter how insane Merlin's initial claims may seem (or however badly he goes about explaining it), he's always — always — proven to be right by the end of the episode.
Although this is finally subverted by The Dark Tower, when Merlin is trying to get the Knights to follow him. Arthur, being his usual Genre Blind self, starts to ignore him, but the Knights point out that it can't hurt as they're already lost, and ask Arthur to give him a chance.
Intentionally invoked by Frank in Seven Days. When a journalist is about to expose the government's time-travel experiments, he confirms her story on national television. He then goes on to say that he is the only man that can time travel, which is why the CIA let him out of the psych ward so he can pilot the ship that runs off of alien technology found at Roswell and designed by a sexy Russian that totally digs him. He (and the journalist) are laughed off the show.
Interesting case on Wire in the Blood: after the police crack the M.O. of a serial killer, it becomes vitally important to alert his latest prospective victim (who is already waiting to meet him) to the danger, without spooking her into hanging up or dismissing the call as a prank. Psychologist Tony Hill immediately demands that he be given the phone; he then adopts exactly the right inflection so that she not only listens to him, but believes him, gives the police her location, and agrees to lock herself into a bathroom stall until he will arrive, using his name as a pass word. This is an inversion in that it is the police convincing a citizen of a sinister plot and not vice versa, and an aversion in how professionally the task is handled. However, while Hill is a brilliant theoretical analyzer of criminals, he is also shown as very socially inept and in fact often more of a liability when interviewing friends and relatives of victims. For him to be that convincing is actually out of character, which might count as a hyper-aversion.
Played for laughs in an episode of The Goodies called Invasion Of The Moon Creatures — the audience has followed everything that happened and knows that it's true, but of course, it sounds insane summing it up. Context: Tim and Bill have been brainwashed by moon rabbits, and Graeme pleads for help with the authorities.
Graeme:(in close-up) Anyway, I sent that rabbit up to the moon...uh, that was Flopsy. But he didn't come back, so I sent Tim and Bill up to the moon to see what had happened, and when they got up there, they found all these...carrots. And then hundreds of rabbits attacked them and overpowered them...(zoom out to reveal two uniformed men are grabbing him) ...and they've just gone into the space-burrow and they've met Big Bunny. (gets fastened with sign reading 'LOONY — handle with care') No, honestly, it's the truth, it is the truth, and Big Bunny's teaching them to say 'Nyeeeeh, what's up doc'! (gets stuffed into a crate reading 'TO THE FUNNY FARM — this side up')
The phrase is spoken by Britta when she is trying to unsuccessfully convince Tory and Abed that their friend Lukka is actually a genocidal war criminal.
Invoked by the Greendale Air Conditioning Repair Initiation. It's supposed to be secret, and so they kidnap people in the middle of the night, there's an astronaut in the corner making paninis, to ensure that any story would sound insane.
Dean of Air Conditioning Repair: We don't want you to tell anyone about this, and if you do, we don't want them to believe you. Isn't that right, Black Hitler?
In the Grimm episode "Woman in Black", Nick is desperate is convince his Muggle girlfriend Juliet that Wesen are real so that she will accept that it is possible that one is trying to kill her by magic and go to the hospital. So he takes her to his aunt's Trailer Full of Crazy, shows her all the medieval weaponry, the books of Grimm lore (in languages she doesn't understand and full of gruesome illustrations) and the collection of Nazi propaganda films and earnestly explains that several people they know are monsters that only he can see, pausing every few sentences to beg her to believe him. For obvious reasons, she thinks he's delusional, and he can't get her to the hospital until after she collapses.
The next season he gets to try this again as a case of Magical Amnesia has wiped Juliet's memory of the event. This time he is much calmer, and makes sure that he can back up his claims by actually having some friendly Wesen transform into their Game Face in front of her.
Arcanum's (in)famous X-Files quest ends this (as well as It Was Here, I Swear) way: when you try to expose the conspiracy, you realize your proof was just, let's say, stolen. For added trauma, when you return to the secret facility where you found it, there's nothing, not even a brick. There are even a number of relatively obscure minor characters (along with a major one) to whom you can present your evidence, but they all either end up dead, have the files stolen from them, or are actually working for the conspiracy.
In Starcraft: Brood War, Aldaris incites a major military revolt and goes off on a mindless tirade about how evil the Dark Templar are and how they would doom the Protoss society. Just as he is finally defeated and starts to explain what he's discovered, Kerrigan pops in and assassinates him. The heroes eventually find out the hard way that Aldaris was right two campaigns later....all because the guy descended into a raving lunacy rather than rationally approaching the dilemma.
Almost completely subverted by Zeratul in StarCraft II. True enough, he starts out as if he's going to play this trope straight, coming to Raynor in a dark corridor and acting all crazy and hurried, but he does give ol' Jimmy all of the information he has, expressed as logically as possible. It's also hard to fault him for boarding the ship in secret, because, well, he's a Protoss (and a Dark Templar to boot), and that's just the way they do things.
In Warcraft 3, the Prophet Medivh could have done a much better job of warning the human leaders of their impending doom, if only he didn't barge into the throne chamber uninvited in the shape of a raven, transform into a human before the King, insult him, and then proceed to ramble about doomsday like a lunatic.
Considering that the magi of Dalaran and the elves of Quel'thalas were very much aware of the existence of demons, all the Prophet really had to do was bring up the topic and say, "yeah, they're coming."
Subverted in Persona 4. After trying out the local rumor (looking at a blank TV screen on a rainy night will reveal your soulmate), the protagonist, Yosuke, and Chie are all talking to each other about their experience the previous night. The main character, unlike the other two, was a bit more hands-on, and managed to fit his head into his TV, which he then calmly and casually explains to them. Thinking it to be dream or a bad joke, Yosuke and Chie take him to the electronics aisle of the local department store, sarcastically suggesting that he could climb right in through one of the flatscreen televisions. When they suggest for him to prove what he said that he did, he promptly sticks his hand into the TV, and then, when curiosity overtakes him, his whole upper torso, at which point Chie and Yosuke begin freaking out.
Unfortunately played straight if he tries to tell his uncle about it later. Despite the TV in the room.
In Mass Effect, the Council is generally considered Too Dumb to Live for ignoring your warnings about the Reapers. But then again, Commander Shepard probably could've come up with some much better arguments.
In the final scene of Wing Commander IV: The Price of Freedom, Blair, having witnessed evidence of Admiral Tolwyn's treason, interrupts a Senate hearing to try and present his case. The player is presented with dialogue options that determine how he goes about this, but the straighter you play this trope, the less likely the Senate is to actually believe him, to the point of bad ending yourself.
In The 1st Degree: James Tobin goes into this a few times. What really makes him look bad is how early on, he changes most of his story, saying that he was so scared and that he did not think anyone would believe him. He even admits to shooting himself in the leg because he wanted to make the situation he was in look like like it was self-defense.
Averted / Defied in Gothic II. When the Nameless Hero has to gain Paladins' support against the dragons in Valley of Mines, he simply tells their commander, "The question is not if you should believe me, but whether you can afford to not believe me if I'm telling truth." It works pretty well — the Hero is sent to the Valley for confirmation.
In the second episode of the The Walking Dead the player can get one of these. When everybody is about to chow down to some nice human meat you have four choices, one of which is ITS PEOPLE, to which the reply is "yes Lee, we're all people in here."
Averted and Lampshaded in Girl Genius when Agatha tries to convince Von Mekkhan that she is the Hetrodyne heir. Von Mekkhan has seen stranger things than talking cats, and while he has seen a lot of pretenders come by, he is willing to give Agatha the opportunity to make her case.
In the commentary for "Homer's Enemy" (featuring the line "This whole plant is insane! Insane, I tell you!") the writers note that if you're trying to convince people you're not crazy, it's not a good idea to end any sentences with "I tell you." Or worse, "I tells you."
Lampshaded in one "Treehouse of Horror" story where Kang and Kodos abduct Homer and spray him with booze before releasing him so that his warnings will be dismissed as drunken ravings.
Professor Farnsworth's effort to explain the dark secret of Slurm is ruined when he identifies Fry as his uncle from the twentieth century. Which is possible, but presumably rare enough that when Fry denies it they assume he's just crazy.
Plus, he's the professor. Pretty much anything he says has a fifty-fifty chance to be dismissed on its own merit, and rightfully so.
In "In-a-Gadda-a-Leela," the crew discover that Earth is going to be destroyed by a giant automated death-sphere-ship thingamabobber, because it's "censoring" inappropriate planets by destroying them. Farnsworth states that people will listen to rational, intelligent people such as them. They emerge seconds later in robes and signs, saying "The end is near!" and "Repent!"
In an episode of DuckTales, Ma Beagle's latest scheme involves pretending to be married to Scrooge McDuck. Scrooge's attempts to deny being her husband fall under this trope, especially when she demands a "divorce" (meaning that she would get half his fortune), and he blurts out that he'd rather "stay married," which of course the judge interprets as meaning they already *are* married...
Duke and company in G.I. Joe: Renegades. The kind, benevolent, paragon of corporate responsibility that is Cobra Industries couldn't possibly be evil, could they? Starts to be gradually subverted as word of their heroic exploits gets out, and even Flint sees evidence that something much bigger is going on.
The protagonist in Looney Tunes' One Froggy Evening follows this trope to a T when he utterly fails to convince anyone (talent agent, theater full of patrons, a policeman) that he is in possession of a singing frog.
In Justice League Unlimited, Supergirl has vivid recurring nightmares about killing people. She goes to Green Arrow who is naturally skeptical. Then The Question overhears her and is so certain that it's part of a deep government plot that even Supergirl becomes skeptical. He is eventually proven right.
In Danger Mouse On The Orient Express, Penfold has a difficult time getting Greenback's agents and even DM to believe that the important document to be transported to London got eaten by a fish, which did eat it when Penfold was submerged in a Venice canal. Later in the episode, the fish, with said document in its mouth, is served to Greenback for lunch on the train ("So...the half-witted hamster was telling the truth!")
Jet from Avatar The Last Airbender does this when he tries to convince the people of Ba Sing Se that Zuko and Iroh are Firebenders.
In this video, it's mentioned that one of the unconscious things a liar does is say things like "Believe me" or "In all Candor."
When the news of the Watergate scandal initially broke, Attorney General John Mitchell's wife Martha began calling reporters insisting that the White House was behind the burglary. No one believed her until months later when investigations confirmed her allegations. As a result, she now has a psychological phenomenon named after her.