Mal: That's great! What?
In an unfamiliar social environment, a character does something that he thinks is mostly innocuous, either intentionally or by accident. Unfortunately, in this society, said act constitutes Throwing Down the Gauntlet, and will result in him engaging in a Duel to the Death, possibly on the spot. Oddly enough, the people from the local culture never seem to grasp the concept that different cultures do things differently, so they never understand the poor foreigner's plight, and he does not get a free pass for not understanding the gravity of what he just did. Sometimes this is justified by them being Jerk Asses who do this sort of thing deliberately.
- In Kyo Kara Maoh!, Yuri accidentally proposes to Wolfram by striking him across the left cheek. Wolfram is so embarrassed and furious that he throws the tableware to the floor- resulting in Yuri accidentally accepting Wolfram's duel challenge by picking up a knife.
- In Ranma ½, Girl-Ranma does this in Shampoo's village by eating the prize that Shampoo was to win. Shampoo challenges "her"; Ranma defeats Shampoo, and winds up earning a Kiss of Death. It eventually turns out that if Ranma had fought Shampoo in his true male form and won, he would have successfully proposed marriage to her instead... a pity he didn't learn this until after he'd beaten her a second time.
- In The Perils of Innocence, Dr. Aymler tries to greet a goblin guard outside Gringotts by shaking hands. The guard comments that in goblin culture an outstretched hand would initiate a duel, while nodding is their preferred form of greeting.
- In 1632 high school Jerk Jock Chip Jenkins, angry at what he sees as someone moving in on his girl, punches Alex MacKay in the teethnote at the Thuringan Gardens. MacKay, being the product of his times, views this act as the prelude to a duel and announces that his choice of weapon will be cavalry sabres. For bonus points, Alex is a professional soldier with significant combat experience. It's fortunate for Chip that authorities Alex will defer to intervene.
- In Anne McCaffrey's Acorna Series, Acorna often unnerves her fellow Linyaari by smiling human-style (with teeth showing). Among her people (Acorna was raised by humans since she was a toddler), baring your teeth is a display of naked aggression, akin to walking around with your fists up.
- The Final War of the Bolo continuum was begun in part due to standard Melconian First Contact procedure: Enact a Non-Intercourse Edict until the governing body has come to a conclusion. The Concordiat saw this as a sign of aggression and the situation deteriorated from there.
- Codex Alera:
- When Tavi first encounters Ambassador Varg of the Cane in Academ's Fury he sees a guard dealing with the frustrated 9-foot tall wolfman being hesitant and trying to defuse the situation calmly. While normally acceptable action for dealing with humans, Tavi realizes if this wolfman is like predators back in his home valley then it is the wrong move. He moves forward, ordering the guards and stares down Varg who is about 4 feet taller and could rip him apart with ease going so far to put a knife to Varg's throat and while terrified won't back down. He also deduces that bowing would be equally dangerous as prostrating could be seen as being prey-like. Instead, he copies Varg's raising of the neck just slightly. Varg is impressed enough to leave until a later time.
- This is discussed in Princeps' Fury when the Princeps of the realm is leading with Ambassador Varg two fleets back to the Cane homelands. The Princeps is having Alerans tutor Cane in their language and the Cane tutor Alerans in their customs and language. He figures if there is to be more fighting between them, it best be for good reasons and not a miscommunication.
- Dune: In their meeting, Stilgar walks up to Duke Leto Atreides, gives an appraising look, and spits on the floor in front of him. Gurney Halleck, with his Undying Loyalty to Duke Leto, is immediately ready to slay Stilgar on the spot for such a brazen insult. Fortunately, Duncan Idaho quickly intervenes and explains that Stilgar's gesture was courteous. On Arrakis, a planet where water is so rare and precious, shedding a few drops of moisture at someone's feet is a sign of respect.
- The war with the Formics in Ender's Game started because of this. It is not uncommon for them to kill another queen's drones to send a message; as they are a Hive Mind, the life of any one individual drone is meaningless to them. When they first made contact with a human spaceship, they killed everyone on board, under the same reasoning. Humans, of course, took this as an act of murder. Once the Formics figured out that humanity were individuals and they had slaughtered intelligent, thinking people, they were horrified to their cores and nearly gave up all hope of ever calming humanity's wrath toward them.
- In the Consul's tale in Hyperion, he recalls his friend having an altercation with a group of locals on a foreign planet. The locals interpret his behavior as grounds for a duel. They toss him a sword, and he simply watches it fall to the ground, not understanding. Not picking up the sword doesn't cancel out the challenge, unfortunately.
- In Terry Pratchett's Johnny Maxwell Trilogy, Johnny bumps into an alien. Trying to look harmless, he shows his empty hands and smiles. The alien returns the gesture... spreading her claws and showing off her teeth. Also, several of Pratchett's books contain a point of advice: Never grin at an orangutan.
- In Robert A. Heinlein's The Moon Is a Harsh Mistress a teenage girl flirts with Stu, a tourist from Earth. He takes the initiative and tries to kiss her, not realizing that this is a capital offense. Partially justified, as the Loonies invoked this as part of their justification for their planned independence war.
- In the Starfire series by David Weber, the Orions consider a toothy smile a challenge. There is also an inversion where a person mistakes an Orion's toothy smile for a friendly gesture.
- One of the characters in Timeline does the opposite. An opponent throws down the gauntlet to show his contempt, but our hero apparently didn't know that picking it back up meant he accepted.
- In a Xanth story by Piers Anthony, Dor meets a giant spider, and tries a "hug" gesture to show friendship. The spider thinks he is readying his fangs.
- Babylon 5:
- "There All the Honor Lies" narrowly averts this when Sheridan accuses a Minbari of lying, but Delenn vehemently explains that the accusation would have called for an immediate and fatal response if the Minbari had been present.
- The Earth-Minbari War started because of this trope. The Minbari ships approached with gunports open but weapons powered off; to the Minbari warrior caste, this was a gesture of respect (and symbolic of "my hands are empty"), while to the humans it looked like the ship was about to fire, compounded by the mess Minbari electronic warfare was (unintentionally) making of EarthForce sensors, so they couldn't tell whether the weapons were armed or not. At least one Minbari realized it was a bad move; Dukhat attempted to order the gunports closed once he realized it had been done, but too late.
- On one occasion, a visiting Minbari battle cruiser greeted Babylon 5 in the same manner, and was almost fired upon. It didn't help that the commander in charge of the vessel, Alyt Neroon, refused to explain himself. It took the intervention of Ambassador Delenn to avoid hostilities.
- Blake's 7. In "Power", Avon is captured by the leader of a primitive society, and grabs his arm to stop him hitting his wife. As their society is based on Asskicking Leads to Leadership as well as misogyny, he assumes that Avon is challenging him for leadership.
- Firefly episode "Shindig": Mal hauls off and decks Atherton Wing after the latter hits the former's Berserk Button by implying that Inara is a whore (Mal may not respect her job, but Atherton disrespected her). Turns out that punching someone in a social function on that planet is considered a formal challenge, and Mal ends up having to fight a sword duel over her honor.
Mal: Use of a sw-what?
- Star Trek: Voyager: One episode has Janeway insult an alien race by putting her hands on her hips, provoking a conflict due to the "obscene gesture". Things get smoothed out in the end, though; even as Neelix was defusing the immediate diplomatic situation before it could turn violent, the Emergency Medical Hologram had developed the cure for a serious plague.
- Star Trek: Deep Space Nine: In episode "Apocalypse Rising", Sisko is pretending to be a Klingon, and as part of the effort, strikes Worf with the back of his hand. Worf then asks if he meant to challenge him to a battle to the death and suggests to simply strike him with his fist instead. Thankfully, this was part of the rehearsal; it did not actually come up when it had to be done for real.
- Star Trek: Enterprise has a group of aliens storm out of a diplomatic meeting in rage, with the crew having no idea what pissed them off. Ultimately, they have to go track them down to figure out how to get rid of some Alien Kudzu; it turns out that their offense was eating where the aliens could see it, something that is extremely private in their culture. Hoshi is able to gain their forgiveness and assistance in the end.
- In Dominic Deegan, Serk Brakkis insults Lars Sturtz's son, Szark, to Lars' face, mocking his (by then in-the-past) penchant for loving duels to the death... and implying that Szark gets off to it. Donovan Deegan then slashes his initials into Serk's pants in response. As it turns out, slicing someone's clothes with a sword constitutes Throwing Down the Gauntlet thanks to Serk's rule-lawyering.
- Critical Role: In Campaign 3, during the masquerade ball in episode 13, Ashton gets spotted by an antagonist they'd met a few days earlier, thanks to Ashton wearing a mask of the Nightmare King (whom the antagonist had been working with), and then gets confronted by the antagonist's Hired Muscle, General Ratanish. Ratanish rips the mask off Ashton, who promptly slaps him in the face. The general just slaps him back, and after some more intense (but polite) escalation, takes him outside.
- Noah Antwiler once recounted a tale of the one time he played Legend of the Five Rings where his ignorance of the setting's customs (and the other players' unwillingness to explain them) led to him being challenged to a duel that he promptly lost.
- Ed, Edd n Eddy: In the episode "Dueling Eds", Eddy inadvertently disgraces Rolf's customs and family honor by throwing one of his cucumber balls at a fence. Double D forces him to give Rolf a flower as an apology... but it turns out that said plant is "the Potted Shrub of Ridicule" and an even greater insult in Rolf's country. Rolf is so pissed at this that he challenges Eddy to a duel.
- Inverted in The Simpsons, when Homer discovers that he can get his way in all sorts of situations simply by Throwing Down the Gauntlet, and starts Glove Slapping people left, right and centre not expecting it to be picked up. Then he tries it with a Southern Gentleman...
Homer: Why oh why did I slap a man who says "suh"?!
- Storm Hawks: At one point they take the Sky Knights to Junko's home, where Piper accidentally bumps into someone. She raises her hands placatingly — and Junko hastens to intervene, because this is how his people challenge each other to a fight.
- Teenage Mutant Ninja Turtles (2012): In "The Moons of Thalos 3", Leonardo is negotiating a tentative truce with the Salamandarians to allow them to work together to escape the moon. Just as it seems he has succeeded, he extends his hand to shake hands with the Salamandarian commander, only to discover that the extension of a open hand is tantamount to a declaration of war in Salamandarian society.
- Japanese culture has a lot of non-verbal signs that can be easy to botch if you're a gaijin. But there was one even locals could fall for: in the era of the samurai, emphatically striking one's sheath, or saya, with the sword's guard was a gesture of a challenge. Given that this is also the culture which invented Iaijutsu, this little tradition probably kept the number of warriors with loose saya rather low.
- Chimpanzees and many other apes consider showing teeth a sign of aggression or fear. Do not smile at them toothily.
- Eye-contact is considered a challenge by primates, felines and canids. Wild canids, that is. One of the things that notably separates domesticated dogs from wolves is that dogs will look a human in the eye.
- A lot of Flame Wars start this way. The lack of facial cues can turn an innocuous statement into an insult.
- Touching hair was considered a grave insult in Fiji that merited mortal retaliation (and worse) before the encounter with the Europeans, especially the hair of a chief. Several early European visitors to the island found this out the hard way (especially Reverend Thomas Baker, an English missionary, in 1867).