One character jumps to the most obvious conclusion from what he or she has just observed about another character. The resulting argument then proceeds in a one-sided manner, so that the other side doesn't get to tell their side of the story (which is always the correct one). Expect to hear "'But...' 'No buts'" in there at some point.
May facilitate an Oops... I Did It Again plot. Should the culprit finally realise the truth, and possibly be humbled enough to listen this time round, the victim may call out I Warned You (or more specifically "I Tried To Warn You").
- Ranma ½ pretty much lives on this trope, with Akane barging in with fist flying and Ranma (social retard that he is) usually too tongue-tied to do more than stammer out a "Let me explain" before going sub-orbital. Maybe one time out of ten is the incident that draws Akane's ire actually Ranma's fault. (Although, to be fair, there's much less of that in the manga)
- It's even Lampshaded at one point, where Akane asks why didn't Ranma just explain what was going on, and Ranma replies, "Have you ever listened to anything I say before you pummel me?"
- Happens in the latter part of Code Geass when the Black Knights, having heard some convincing half truths about their leader Zero from Schneizel, decide to betray him by luring him into an execution squad. Kallen, who has been sent to retrieve him and has been commiserating with him on the way, calls the situation one-sided, before her comrades tell her to get out of the way or else be shot under suspicion of being under Lelouch's geass. At this point, it's completely obvious that the Black Knights are completely set on executing their leader, not to mention that Schneizel, who always has a backup plan, is behind it, so Lelouch decides to lie to everyone that he used them, Kallen included, in order to have her spared.
- In Fullmetal Alchemist, Alphonse suspects Edward gave him Fake Memories of his life, and accuses him of not telling him. The events of consequence vary by adaptation; in the 2003 anime, before Ed can get in a word Alphonse runs off, leading Ed for an episode long hunt for him before he can finally ask his real question, whether or not he hated him for what happened to him. The manga and anime adaptation mercifully averted all of this by having Winry stop Alphonse and call him out on not realizing how worried sick his brother had been every night in bed over him.
- When Huey, Dewey and Louie first tried to join the Junior Woodchucks — according to the Don Rosa story "W.H.A.D.A.L.O.T.T.A.J.A.R.G.O.N.", they were outright rejected for calling Elvira Duck "Grandma", as they usually do. The Senior Woodchucks were scandalized that they would address their founder's daughter that way. One of the boys tried to explain but got a "No buts", and they were only got allowed back when Elvira explained she's technically their great-grandmother, which of course instantly turned them into desirable material instead.
- Archie Comics' Sonic the Hedgehog: After the events of the Iron Queen's occupation of New Mobotropolis, which briefly resulted in NICOLE being hijacked and forced to help trap citizens in their home, Mina, hoping to spread awareness regarding possible problems with NICOLE being compromised again, uses her status as an Idol Singer to her advantage to start spreading such messages with her music. It's only after her first song is sent that she discovers from Sonic and Sally that NICOLE had actually broken free from the Iron Queen's control, but was working undercover to protect as many people as she could, which Mina was not aware of beforehand. This, combined with a Hate Plague generated by Ixis Naugus, eventually results in NICOLE being banished from the city, something Mina never intended.
- The Stalking Zuko Series after being confronted by his therapist, Dr. Wang, Jet begrudgingly admits to himself that "Lee" is probably not a firebender since he has seen Lee's physical prowess and never saw him firebending. Then Jet realizes that he seen Lee's uncle Mushi warm up his tea without any means to, make gallons of tea without any firewood and able to be naked in the middle of early spring. Jet concludes that Lee never responded to his accusations because he's not a firebender and to protect his uncle from scrutiny.
- In chapter 15 of the Love Hina fic Contract Labor, Motoko overhears Kitsune talking to Haruka over the phone about an incident involving Keitaro, Naru, and the police. Given her All Men Are Perverts mentality, Motoko automatically jumps to conclusions and assumes that Keitaro had assaulted Naru; Motoko attacks Keitaro as soon as they return home from the police station, only discovering after the damage is done that Keitaro actually saved Naru from being kidnapped and possibly gang-raped. As a result, Motoko kicks off a series of events that result in her not only being evicted from the Hinata House, but all but disowned by her family completely.
- In Fullmetal Alchemist fanfic Build Your Wings on the Way Down, because of the Gate Ed only knows Roy through his actions in Ishval and knows the darker aspects of biological alchemy. So when Roy praises Shou Tucker's work with chimeras, Ed gets the impression that the military condones and approves of Tucker's actions and Roy has no respect for human life. Edward later finds out that he jumped to conclusions and pegged Roy wrong when Roy is horrified at Tucker turning his daughter into a chimera.
- In Im Giving You A Night Call all of Mustang’s aides, especially Hawkeye hate Edward and are very cold to him when they first meet him. While Edward had a justified reason for leaving Mustang as far as they know the love of Roy's life cruelly dumped him for no reason and is very hateful towards him.
- In The Sixth Sense, the audience is not aware that the main character is dead, so the restaurant scene goes like this: Man shows up a little late for his wife's anniversary dinner, but no matter how hard he tries to reconcile, she won't even talk to him; then she grabs the check before he can touch it, throws him a chilly "Happy Anniversary," and stalks out. But once you know that he's dead, it's: She's keeping his anniversary dinner X years after he died!! Her entire character (in other scenes as well, such as where it appears she's ready to cheat on him) changes based on that info.
- Hitch. The title character's love interest Sara has a friend who slept with a guy who dumped her the morning after. On the way out the door, he makes an offhand comment, "Date doctor my ass." Sara makes it her mission to find the date doctor and expose him, blaming him for enabling the scumbag to use her friend. When she finds out it's none other than Hitch, the guy she's been seeing and whom she likes, she trashes him and his completely innocent client in her gossip column. This effectively ruins his reputation and livelihood. The kicker? He hadn't even worked with the jerk who dropped his name, and Sara hadn't bothered to find out the truth. And when Hitch is still hurt by her actions and doesn't take her back immediately, he's the one who ends up having to make a grand gesture to make it up to her while she gives him the cold shoulder.
- Funny thing is, her friend immediately believes Hitch when he explains that he never helped the jerk, even explaining why he does what he does (to help shy guys make that first step), while Sara just assumes he's lying to protect himself.
- Gods Play: Happens when William tries to explain being a shifter to Toby when he's in a compromising situation
- Harry Potter: Sirius Black spent years in Azkaban Prison because everyone who didn't know Peter Pettigrew was a Death Eater assumed Sirius betrayed the Potters and killed Peter Pettigrew and several muggles. It was eventually revealed Peter faked his death and framed Sirius with everything.
- Buffy the Vampire Slayer: This causes the major climax in the Season 5 episode "Blood Ties" when Dawn discovers she's the mystical Key.
- She overhears only the first part of a conversation between her mother and sister:
Joyce: She yelled at a teacher. The things she said, Buffy, I mean she never used language like that.
Buffy: She probably feels like she can say or do anything right now. She's not real. We're not her family, we don't even know what she is.
- Dawn immediately runs off into danger and totally misses the rest of the conversation:
Joyce: How can you talk about Dawn as if she's a thing?
Buffy: I'm not! I'm just saying that's probably how she feels.
- She overhears only the first part of a conversation between her mother and sister:
- 8 Simple Rules: John Ritter continuously berates one of his daughters for shoplifting. In reality, the friend she was shopping with did it.
- Full House:
- D.J. was trying to take a beer can away from three boys at a school dance when her uncle Jesse catches her in the hallway and wrongfully accuses her, until one of the boys who were drinking confess to Jesse (after he apologizes to D.J.). Slightly different in the respect that D.J. did get to tell her side of the story, but even after answering every one of Jesse's questions, he still didn't believe her and didn't even consider the possibility she was telling the truth.
- Jesse himself became the victim of this trope the following season when he tried to borrow a truck to get to his wedding to Rebecca on time, only for the sheriff, who is also the driver's cousin, to arrest him for stealing the truck. Laser-Guided Karma, anyone?
- El Chavo del ocho: Whenever Doña Florinda is sure Don Ramon hurt or tried to hurt her son, she'll certainly slap him and never allows him to explain. She's lucky he Wouldn't Hit a Girl.
- Guild Wars plays with this on multiple levels. The Charr in the first game are presented as an Always Chaotic Evil race of invading fire-worshiping hellcats who live to destroy and enslave, and like to eat their human prisoners, and that slaughtering and torturing the Charr is not at all a bad thing. Both the characters in-game and the players were lead to believe this was the truth. Cue Guild Wars 2 revealing that all that was only propaganda from the human kingdoms - the Charr are far more complex, never ate people, and the invasion was their struggle to reclaim their occupied homeland.
- Mass Effect: Geth. For three hundred years every race in galaxy though they were murderous synthetics because quarians, who barely avoided total genocide at their hands, claimed so. Geth were just defending themselves and minority of quarians who claimed that geth won't rebel. Better yet, they still think of quarians as their Creators and ready to serve them. No one knows about it, because they isolated themselves so galactic races won't see them as threat. Geth heretics didn't help the case either.
- I Am Weasel: the Weasel berates I.R. Baboon for coming late for a motorcycle test and refuses to listen to whatever stupid explanation he has. He finds out too late he forgot the brakes to the motorcycle, leading to wacky hijinks.
- Mickey Mouse Works: Daisy's berating Donald Duck for (for example) dancing with her neighbor (the neighbor literally dragged Donald into it), while he's supposed to be building a brick wall at her house.
- All Grown Up!, "Brother, Can You Spare The Time?": Dil appears on a talk show, "What's Your Tragedy?", about Tommy abandoning him upon winning an award in filmmaking, prompting booing and jeers from the audience when Tommy shows up to explain his side (basically, that it's not the case at all).
- Rocket Power, "Race Across New Zealand": Ray Rocket won't stop flapping his yap on how his son Otto doesn't like to lose to hear out his daughter Reggie's own grievance: that she managed a tie in the previous race, and the only thing Ray cared for was Otto's loss.
- Many Looney Tunes shorts operate multiple gags on this premise, most notoriously "Bugsy and Mugsy", where Bugs is able to convince Rocky the Gangster that his sidekick, Mugsy, is trying to kill him.
- The first Shrek movie pulled off a two-sided version of this. Shrek half-overhears a conversation between Fiona and Donkey, but misses the most significant part: that Fiona turns into an ogre at night. The next day Shrek and Fiona both assume that Shrek heard the whole conversation and each jump to a false conclusion.
- The Shrek conversation is skillfully crafted to become two separate scenes based on whether or not you know the piece of information; the audience is aware of it at the time.
- A variation of this takes place in How to Train Your Dragon (the film), when Hiccup tries to tell his father that he really can't kill a dragon. (He knows this to be so because he just had a golden opportunity to kill one, the Night Fury he later names Toothless, and couldn't bring himself to do it.) Stoick, his father, keeps brushing off his objections as fear and browbeats his son into agreeing to enter dragon training. Hiccup even lampshades the trope by noting that "This conversation is feeling very one-sided."
- In the Sadie Hawkins dance episode of As Told by Ginger, Darren thinks Ginger is jealous because Courtney invited him to the dance while Ginger is going solo (Ginger's actually trying to tell him that Courtney meant to invite his older brother Will).
- Played and Lampshaded in the TaleSpin episode "It Came From Beneath The Sea Duck" when Rebecca is berating Kit for taking Molly out of the house (for a number of convoluted reasons in reality). Baloo suggests letting Kit explain what happened, only for Rebecca to shush him as well.
- In an episode of King of the Hill Boomhauer's brother is getting hitched, and quickly proves unfaithful and resorts to all sorts of sleazy antics, Boomhauer constantly attempts to stop and scold his brother, but is constantly manipulated to look like the culprit himself, leading to a long drawn chewing out from Hank, complete with the cliched booming of "BUT NOTHING!!!" whenever he tries to babble an explanation. Oddly subverted when Hank later confronts Boomhauer over what's going on and gets the truth, though even as he is apologizing to Boomhauer he won't let him get a word in.
- Fritz the Cat: The pig cops in the 1972 movie have a conversation like this in the synagogue. One of them desperately tries to inform the other that he saw Fritz, but the other keeps slapping him to make him shut up out of respect for his Jewish faith.
- The Simpsons: When Bart tells a dirty joke to Reverend Lovejoy, his wife and daughter while visiting them at home he is thrown out of the house. As Bart starts stuttering "but, but, but...", trying to explain himself, Helen Lovejoy thinks he is repeatedly saying the word "butt" and asks him to "make it stop!".
It doesn't even have to be an argument, as long one character won't stop talking long enough to hear out the truth
- Almost every arc of Higurashi: When They Cry runs on this trope.
- In Full Metal Panic!, Sousuke seems to have this going for him whenever anyone gets too direct about trying to convince him that someone has feelings for him. Many times, while they're in the process of trying to explain to him why someone is acting strange around him, he'll end up interrupting them before they get too direct, coming to his own outlandish conclusion as to the reason why. Most people just sigh and shake their head. This tends to happen the most in relation to Tessa.
- In Tsukigasa, the facts everyone knows are that Azuma cut off Kuroe's arm and Kuroe ran away and joined a band of robbers. Everyone has their own idea of what actually happened and why it happened, many of which are misinformed because they are unwilling to just put it all out in the open. Eventually all the pieces are dragged out one by one and things get resolved but it takes awhile.
- The anime adaptation of THE iDOLM@STER: Cinderella Girls has Rin getting into trouble with a police officer. He assumes she was bullying a young boy, and it isn't until they're at the station that he learns that she was actually helping the kid.
- Hey Arnold!, "Arnold & Lila": Lila won't stop talking long enough to allow Arnold time to say he didn't write "Arnold and Lila" on some wall. Helga had scrawled "Lila" in place of you-know-who to hide her dirty laundry... only to create this other dirty laundry.
- All Grown Up!, "It's Cupid, Stupid": Nicole won't stop being excited over Tommy long enough for Tommy to tell about Chuckie wanting to ask her out to a Valentine's dance (Imaginary Love Triangle).
- Danny Phantom, "Splitting Images": Monster of the Week (not really a monster, but who cares?) Poindexter believes Danny to be a bully after Danny dealt Dash (an actual bully) some much-needed humiliation, and, yep, won't even let Danny explain himself. Once the initial confrontation is over, it's just taken for granted that Danny apparently was wrong, in an Anvilicious "With great power Comes Great Responsibility" Aesop. One that he seems to forget on several occasions and has even has to visually re-learn within the first Made-for-TV Movie.
- A Charlie Brown Thanksgiving: Peppermint Patty invites herself to Charlie Brown's house for Thanksgiving dinner, not giving Charlie the chance to explain that he's going to his grandmother's for dinner.
- She is eventually called out on it after Marcy asks her if Charlie Brown really did invite her, Franklin, and Marcy over for Thanksgiving Dinner, however. Feeling guilty about her actions, she apologizes to Charlie Brown and they make up.
- This is the basic schtick of Foghorn Leghorn. He goes on and on without letting the other characters get a word in edgewise, then complains how they never listen to a word he says. On at least one or two occasions, the other characters have been seen yelling at the rooster to shut up and hit him on the head with a stick to knock him out.
- Twilight Sparkle did this to herself in the My Little Pony: Friendship is Magic episode It's About Time. She appears before herself to give herself a message, but Past Twilight wouldn't shut up and stop asking questions, so the spell timed out and returned Future Twilight to her proper time. Having only pure speculation based on her future appearance note and the date (next Tuesday morning), Twilight proceeds to disaster-proof the entire town... and slowly drive herself insane with worry about the future. By the time she becomes her future self, we find out that the message was for her to not worry so much about the future.