In Dragon Ball Z Abridged, Gohan asks Krillin if "he used his Kienzan to chop Freeza in half" after using his Solar Flare. Krillin didn't.
In Yu-Gi-Oh! The Abridged Series, Yami rants to Pegasus about all the unnecessary death, expense and pointless angst he's caused by setting up the Duelist Kingdom tournament to try and cheat Yugi out of the Millennium Puzzle. "Did you ever consider just asking me for it? I mean, do you have any idea how much time and money you've wasted with this whole fašade? People have died because you wanted a necklace! I killed a gay clown for Ra's sake!"
In the original series, it's revealed that the Big Five wanted to take over KaibaCorp and merge with Industrial Illusions, and the condition for the merger was Pegasus being able to defeat Yugi, who had defeated Kaiba, and thus help mitigate the blow to KaibaCorp's reputation. Pegasus was on board with this plan because he needed both the "necklace" and the KaibaCorp technology. This also explains the "Kidnap Mokuba" subplot.
In the Yu-Gi-Oh! GX manga, Chronos threatens Sho with expulsion for getting a 0 on a test, having him to duel Judai to stay (with Judai losing his deck if he loses). After Judai wins, Midori Hibiki reports that Chronos read a provisional report, and that Sho got a high score, only having it counted as a 0 for the preliminary report because he didn't write his name. Then again, given that Chronos is a Sadist Teacher with a grudge against Judai, it's possible he never cared if the report was accurate.
In Yu-Gi-Oh! 5Ds, Yusei points out to Z-One at the end that his attempts to save the future from The End of the World as We Know It could've gone a hell of a lot easier had he simply warned Past!New Domino City of the dangers of Momentum and Synchro Summoning than attempting to destroy the city, like he planned. Especially egregious considering how fresh in the minds of its citizens Zero Reverse was, in Past!NDC.
Blood+ has the Schiff, escaped bioweapons that really would like nothing more than to live normal, happy lives. Unfortunately, they have a very, very short life span. They decide that Saya's blood might help... and savagely attack her. They eventually ask politely, and Saya gives them some willingly. Too bad it was all set up as a Let's You and Him Fight. It's actually somewhat justified; having been raised as living weapons, the Schiff have No Social Skills, and thus simply asking for something is an alien concept to them.
In Uchuu Senkan Yamato/Star Blazers, after the crew of the Yamato is forced to destroy the Gamilas (Gamilon) homeworld, Kodai (Derek) is depressed about it, particularly because he and the crew had learned that the invasion of Earth was just to help save Gamilas, and the entire war could have been avoided if the Gamilas had just asked for help...
Unlike many examples of this trope, Nanoha and the other heroes didn't have any alternate ideas for saving Hayate, although it took them a while to find out about the Wolkenritter's goal. The incident is resolved when the Book of Darkness is completed, Hayate manages to reach out to the book itself, and the heroes, the Wolkenritter and Hayate team up to defeat the defense program.
In the first season, Fate Testarossa refuses to ask for Nanoha's help in recovering the Lost Logia, even though Nanoha's only objective was that they were safely sealed. Although this probably wouldn't have worked in the long run anyway, considering the Fate's Mom was going to use them to break reality.
Fate agrees to Nanoha's help in sealing the six Jewel Seeds in the ocean in Episode 9, dividing them between them... which gets her another whipping from her mother for wasting a precious opportunity.
In Junjou Romantica, Nowaki disappears from Hiroki's life for a year without so much as leaving a note. Hiroki is understandably pissed off, and when Nowaki comes back they have a fight that lasts for weeks before finally being resolved. It's not until after they've made up and decided to move in together that Hiroki remembers that, um, actually Nowaki did tell him he was going to leave... and, in fact, Hiroki encouraged him to do so... it's just that Hiroki wasn't paying enough attention to the conversation to remember it afterwards. Ooops. Like Hiroki says, "Wow... that sure makes me look like the bad guy here."
Letter Bee: In the "Letter to Jiggy Pepper" arc, a girl named Nelly and her brother Nello were once friends with Jiggy Pepper before he left town to become a Letter Bee. Nello, dying of a disease, wrote a letter to Jiggy and confessed to being "so angry," which Nelly believed meant that he was angry with Jiggy Pepper, and caused her to steal Lag's crossing pass in order to deliver Nello's letter herself. It turns out that Nello was angry with himself for not being able to get better so that he could protect his sister, he encouraged Jiggy to follow his dreams, and Jiggy left to finance building a church in the village.
Paranoia Agent: Sagi Tsukiko created Shonen Bat only to avoid her strict father's scolding for losing Maromi. but Maniwa revealed that her father always knew the truth: He only went to search for Shonen Bat to avoid the fact that he was so strict and her own daughter feared him, so he lied to the police and took a bat and pretended to search for Shonen Bat to show Tsukiko he cared for her.
In Katekyo Hitman Reborn! if Checkerface aka Kawahira had sought help from the humans rather than use them as living batteries he could have saved many lives. It is Talbot who invents a device that keeps the rings powered for eternity.
In A Certain Scientific Railgun, during the Sports Festival, Misaki kidnaps Misaka 10032, sets all her resources to finding the other Sisters, brainwashes Mikoto's friends, and altogether causes lots of problems for everyone. Her goal was to rescue 10032, keep her and the other Sisters safe, and destroy the organization that was trying to take advantage of their Hive Mind. If she had explained this to Mikoto, then they—two of the most powerful individuals in the city—could have done all this with little hassle. But Mikoto is immune to her telepathy, and she is far too paranoid to work with someone she can't mind-read.
In A Certain Magical Index, Ouma Yamisaka kidnaps Index (blowing up Touma's apartment, a restaurant, and Touma's homework in the process) and tries to extract knowledge from her mind to lift a curse from a woman he loved. Touma tracks them down and says that he and Index would have been happy to help save the woman if Ouma had just asked for their help. Touma easily lifts the curse off-screen.
In Haiyore! Nyarko-san, a time-traveling alien named Yithka appears and attempts to use a mind-swapping gun to "borrow" Nyarko's body, but messes it up and instead swaps Nyarko and Mahiro with each other. After Yithka explains her situation (she needs help dealing with extremists from her time period) and the gang agrees to help, Hasta asks "Why didn't you just tell us that in the first place?" Yithka responds by beating a hasty retreat.
One episode of Hell Girl features a girl who takes in a stray cat and is promptly harrassed by her neighbor, presumably because the neighbor hates cats. She is ultimately driven to sending the neighbor to hell when she finds bagged (presumably cat) meat outside her neighbor's door, with no sign of the cat anywhere. No, it turns out. One of two major twists that episode is that the neighbor had previously grown affectionate with that cat and resented the girl for taking the cat away from her. She hadn't killed the cat; simply stolen it. At the end of the episode, Ren specifically asks the neighbor why she didn't try talking to the girl in order to find a solution, and she says it never crossed her mind. After that, the girl discovers the missing cat in the neighbor's apartment alive and well, along with a zillion photos of the cat all over the walls.
In Happiness Charge Pretty Cure, Iona spends about half of the series demonizing Hime for her Dark Secret of opening the Axia Box, releasing the Phantom Empire. After circumstances end up knocking Iona down a few hundred pegs, she finally asks Hime why she did what she did. When Hime explains and Iona responds why she didn't say so earlier, she's hurt pretty bad to realize Hime tried to, but when you spend most of your time calling her names and trying to turn her friends against her, explanations like that aren't going to get through.
In a 1970s Archie story, a young man kidnaps Betty, under the assumption that she's Mr. Lodge's daughter, in retaliation for Lodge not promoting his father to a middle-management position. When the crook is caught, Lodge tells him that he had in fact made him a vice president.
In the Russian fairy tale, "Tsarevich Ivan And The Grey Wolf", Ivan has to retrieve first a firebird, then a magic horse. In both cases, he breaks into the palace of the Tsar that owns the object and is caught. Afterwards, both Tsars tell him that if he'd simply come to court and asked like a prince, rather than sneaking in like a thief, they would have given him what he needed as a gesture of friendship.
With Strings Attached. After the epic battle on the Plains of Death, George points out to the Hunter that after he learned he could become a dragon, he could just have flown everyone away from the Plains and up to the Twisted Temple, thus avoiding the battle, which was never necessary to their quest.
Imperfect Metamorphosis. All the situation that ravages Gensokyo could have been avoided (or at least mitigated) if everyone had followed the spellcard rules.
Star Crossed, a Lucky Star fic taking place seven years after the anime. The main four find themselves in very bad situations, some of which themselves are their own fault. It's only after they cross the Despair Event Horizon that those still alive remember the promise of friendship they made to each other upon graduating from high school, a promise which they had broken and paid ultimately for. Minami does the same thing in the epilogue, running away from whatever problems she was having instead of asking Yutaka for help (and at a time when Yutaka herself needed help with certain problems courtesy of Konata), and subsequently dies in a divine plane crash out of Japan, failing the same test of friendship that the mains already had.
Rosario Vampire: Brightest Darkness Act I: Apoch and Astreal brainwash Rason and Dark in order to get them to help them fight off their master Ghaldin, but it backfires when Ghaldin arrives and takes control of all four of them. When Ghaldin is defeated, Apoch and Astreal apologize and insist that they only wanted help; Tsukune informs them that the entire group would have helped them if they had simply asked and let them act on their own accord.
The three main protagonist in HorribleBosses could have solved their individual dilemmas if any of them bothered to bring a recording device of some kind to the workplace, rather than scheme up some plot to murder each others bosses You have one boss abusing and verbally assaulting his employee, another demanding that employees be terminated simply for being fat and/or handicapped, while doing cocaine and soliciting hookers, and one boss straight up sexually assaulting her patients and date raping her assistant. This would have been a lawyer's wet dream with proper evidence.
In Avatar, a method of avoiding the conflict between the military and Na'vi had already been put to use in the form of the titular avatars. The main characters were supposed to research the area and diplomatically convince the Na'vi to allow some Unobtanium mining. Unfortunately, the main characters were so busy screwing around that they forgot the whole "diplomacy" thing until their deadline was up, leading to a destructive battle, with hundreds of people dead on both sides. In fact, Jake was in the middle of trying to get the Na'vi out of Hometree before when Quaritch yanked him. If the 'dozer had been a bit slower, if he had gotten into the Avatar bed a few minutes earlier, if Quaritch had been a few minutes later, etc. Noted in How It Should Have Ended .
In one of the deleted scenes, Jake Sully admits that he is in a no-win situation and could only stall for more time by giving Quaritch vital info on the Navi while trying to earn enough trust to convince the tribe to leave their ancestral home.
Heck, in one scene in the movie proper, it's revealed part of Quaritch's motivation was a depressed Sully admitting "It'll never work..." But clearly NOT in a good mood...so, either Sully for making the video...and the 'treason' thing was a bit...overdone.
In The Sandlot, if they had realized the stories about The Beast were urban legends, and had just gone to Mr. Mertle in the first place about the baseball, the whole thing could've been avoided. Mr. Mertle even asked why they didn't go to him first.Scottyhad actually suggested going over and asking before being rejected in favor of Squints' convoluted plan.
In The Adventures of Robin Hood, Robin Hood's first meeting with Friar Tuck results in the two of them crossing blades in the middle of a small lake. After a few minutes of requisite Flynning, Robin offers Tuck free food and ale if he joins his Merry Men. Tuck answers, "If you had said so sooner you could have saved us both a wetting!"
In Sunshine, the events of the film could have been avoided if the characters had all listened to Mace. If they chose to continue their mission instead of taking their ship to the Icarus 1, everything would have gone smoothly.
The main plotline of Brother Bear might never have happened if Kenai had only done a better job of tying up the fish. Rut and Tuke point this out in the DVD Commentary.
In The Little Mermaid II: Return to the Sea, the whole plot could have been avoided if Ariel had just simply told Melody that Morgana would kill her if she were to explore the sea; Ariel even acknowledges that she blew it.
Trust is one of the main themes of Lantana, and in fact Valerie never would have died if mistrust had not come into play. Nik Daniels confesses to his role in her death and it turns out it was accidental with no direct involvement from Nik; he gave her a lift home and took a back road shortcut and she got the wrong idea, panicked, fled from the car and accidentally fell down a ravine.
Anna: Of course, none of this would have happened if she had just told me her secret. She's a stinker.
In Labyrinth, Sarah comes across a worm who helps her into the titular Labyrinth. She almost turns left into a path, only for the worm to tell her to not go that way. Sarah turns around and goes right. When Sarah is out of earshot, the worm says:
"If she had kept going down that way, she'd have gone straight to that castle!"
There's also a case of This Scene Could Have Been Avoided within the movie itself. When Sarah first meets Sir Didymus, he clearly states that he won't let anyone pass without his permission. It takes a violent fight between him and Luto that ultimately ends in a draw before Sarah finally considers asking his permission. (Which even he didn't realize, it seems, he was free to give, which he does.)
In Chicken Run, the chickens could have escaped that farm a long time ago had they actually listened to Fowler's war stories. He was always rambling on about the R.A.F. and the 'old crate', but since they never paid any attention they never realized he was describing the ideal means of escape. They finally listen near the climax, build an aircraft, and escape.
The whole plot of Carry Me Back wouldn't have happened if the Donovan patriarch had at least held on until they got back to the ranch (especially considering the red tape that is New Zealand's funeral code). Because he couldn't wait to shuffle off his mortal coil, his sons have to smuggle him back to the property and pretend he had died there in order to be able to receive their share of the inheritance.
In The Brave Little Toaster, it turns out that the main characters' mission to find their Master was completely unnecessary, since he was going to pick them up in a few days anyway. There is still a benefit to them doing it, though - they started out disliking or at the very least being vary of each other, and the journey caused them to become friends.
In the novel Red Storm Rising, the Soviet Union's largest oil refinery is destroyed by a terrorist attack, and the USSR launches an invasion of West Germany to distract from their true intentions for the Middle East in order to get the oil it needs, intending to use their existing stocks of already existing refined oil to fuel what they expected to be an easy defeat of a NATO surprised by a supposedly unexpected sudden attack. By the end of the novel, the Russians are repelled, and in the final pages a NATO commander quips that if only the Soviets had asked for help, the West would have been happy to sell it to them.
This type of situation was handled far better in the novel The Devil's Alternative, where the Soviet Union is permitted to purchase desperately needed wheat by agreeing to arms reductions, thus averting a similar invasion of West Germany.
One Politburo member actually pointed out that they could simply buy fuel, something they could afford slightly better than losing a war they were far from certain of winning. He was overruled for fear of the scenario mentioned in The Devil's Alternative above; the United States would have them over a barrel (or an oil drum) and could screw the Soviets out of every last red cent of their gold and foreign currency reserves if they so chose. The book is ambiguous on whether or not this would have actually happened. The NATO commander freely admits that they probably would have asked for some sort of concessions as part of the oil deal, but denies that they'd be harsh enough to make the war a preferable alternative.
In the first Vlad Taltos booknote first chronologically, but not by publication order, Vlad makes a complaint of this nature to Sethra Lavode and Morrolan after learning his embezzling employee was their plot to meet with him. Subverted in the next two sentences when he acknowledges that he probably wouldn't have come if they just asked.
The entire goal of Fornia in Dragon is to release the Great Weapon concealed within the sword he stole from him. To do so, he waged a massive war against Morrolan on the off-chance that they would come into single combat in battle, which ends up getting him killed. Later, Vlad comments that Fornia could have just challenged Morrolan to a duel, except that Morrolan had already declared war on him, and a Dragonlord can't resist a good war.
Author Matt Stover presents an interesting twist on this one in Blade of Tyshalle. In the book's prologue, protagonists Kris Hansen and Hari Michaelson plot to get Hari out of Magic School and into Battle School. Their plan hinges on getting Hari to demonstrate his fighting prowess by "saving" Kris from a rival, crippling him in the process. Afterward, the head teacher tells them their plan has succeeded, but laments that another person's dream was crushed so that they could have theirs, adding plaintively "Couldn't you have asked?"
It's played also as a sort of "What the Hell, Hero?" moment. The dean who has been depicted as an antagonist jerk is completely at the end of his rope, almost in tears because whatever else he is he is a teacher who cares for his students.
In Queen Zixi Of Ix (by L. Frank Baum, the author of the Oz series), the title character is a Vain Sorceress who attempts to steal a magical cloak that will grant one wish to each person who wears it. In the end, when her schemes are discovered, the cloak's owners tell her that they would have been willing to let her borrow the cloak and make her one wish, so she had no need to resort to theft. However, this incident convinces the fairies who made the cloak that humanity is no longer worthy of such a gift, and they take it back—so Zixi still never gets to have her wish granted.
In the short story The Necklace a woman asks her friend to borrow a necklace for a party to make herself stand out. Her friend gives it to her but after the party the woman loses the necklace. Rather then tell her friend the truth, she replaces it with a similar but very expensive one and she and her husband work themselves into poverty trying to pay it off. When she see her friend again, its then she reveals the truth to her...only to be told the necklace that was loaned to her was a cheap imitation that was hardly worth anything.
Harry Harrison's novel Invasion: Earth describes Earth's First Contact with two alien races. One of them, pale-white Human Aliens, claim they arrive in peace to protect Earth against their enemies, who are bent on conquering the planet and taking its resources. They set up powerful weapons in Antarctica but require large quantities of radioactive materials to power them, which the grateful Earth governments supply them. When the US and USSR start to suspect their new "friends" may not be telling the truth (like when two major cities get wiped out with Neutron Bombs), they send a mission to the Moon, where the main characters communicate with the other aliens (Wookie-like beasts), who claim the first aliens are the evil ones. The end result is that the Earth governments are supplying the humanoid aliens with resources to maintain the ruse of cooperation while also supplying resources to their enemies for help in liberating Earth. It turns out that both alien races are working together to trick humans out of their resources, which they need to power their ships. After kicking out the aliens, one of the main characters wonders why the aliens didn't simply ask for help while offering their technology in return. She also condemns the military for striking back at the aliens instead of offering help, which would carry more weight if they weren't responsible for millions dying in the most horrific way.
In the Dale Brown novel Shadows of SteelBig Bad Buzhazi is told that he could have avoided getting into trouble with the US had he only destroyed their spy ship but let the crew be, since the US would have swallowed the destruction of the ship in exchange for not letting the truth about it out.
The Tales of the Otori series ends with a fairly spectacular disaster that was considerably worsened by Takeo not telling Kaede that he had gotten another woman pregnant when he left her and thought they would never see each other again. It is worth noting that there were sixteen years during which this information could have been imparted, but every time he considered telling her he kept putting it off. He does, at least, fully acknowledge how stupid he's been, but by then it's too late to solve the problem.
In the Wars of Light and Shadow, the Koriathain Order had been searching for the Waystone of the Koriathain, an enormous Crystal Ball that could amplify their power immensely, for five centuries. Upon learning that Sethvir of the Fellowship had it, they try breaking into his tower and seizing it by force. After being violently repelled by the wards, they are forced to ask him for the return of the Waystone when he returns from a business trip. At which point he mentions that they had asked for the return of the stone (Or assistance in finding it) at any point in the 500 years since they had misplaced it, they would have given it back without any fuss.
In the Jeff Stage novel Chasing Jenny, the Big Bad's goal is to obtain a rare stamp to sell for lots of money. Towards the end, his The Dragon points out that if he really needed the money so badly, the villain could simply have sold the copy of the stamp he already owns. This would have saved several murders, arson and grand theft auto, as well as avoided the strong possibility of getting caught. (The villain's ulterior motive appears to be a grudge against the owner for being a better person than him.)
Live Action TV
In the Star Trek: The Next Generation episode "11001001", the Bynars, a cybernetic and mildly hive-minded Federation species whose "hat" is binary thinking, seize control of the Enterprise in order to save their planetary database, tricking most of the crew into evacuating the ship and then trapping Picard and Riker in the holodeck. When Picard learns about their predicament and asks why they didn't just ask for help, they explain "you might have said no". Riker observes that, as the Bynars only think in all-or-nothing absolutes, the mere possibility of being turned down seemed as bad as a certainty to them. note As for why they didn't think to try asking first, and then steal the ship if told no... Error in Fridge Logic subroutine! Does Not Compute!
The Star Trek: Deep Space Nine episode "The Ship" has this trope as its main premise. The main characters (and several Red Shirt characters) capture a Dominion battleship. The rest of the episode involves the Dominion trying to capture the ship by surrounding it leading to many deaths on both sides. In the end it is revealed that the Dominion were only interested in rescuing a founder who dies during the siege. They would have gladly given the ship to the heroes in exchange for the founder, but they were too afraid that the heroes would kill it to ask. The episode ends with the characters lamenting the fact that all of these people died unnecessary deaths because they wouldn't trust each other.
Pointed out in a Stargate Atlantis episode. Dr. Keller has been kidnapped by a Runner (no, not Ronan) who wants her to treat an injured little girl. Keller would have, of course, treated the girl without a problem, and asks the guy why he didn't just ask. He replies that she might have said no, which doesn't seem to satisfy anyone very well.
In Angel Wesley abducted an infant Connor, believing a prophecy which stated Angel would kill his own son. Later, as Wesley lies injured in the hospital after his plan led to Connor's disappearance into a hell dimension, an angry Fred tells him that the prophecy was a fake, and if Wesley had simply talked to anyone else the tragedy would have never occurred. Everyone else agrees Angel could never kill his son.
On How I Met Your Mother Marshall has a weird phobia about going to the bathroom at work; he feels like all his co-workers are judging him as they see him walk to the bathroom. He tries various ways to go to the bathroom secretly, until finally he just gets over his fear and uses the public bathroom at work without shame. Then Barney (who was also his co-worker) reveals he has a private bathroom in his office that Marshall could have used at any time. In this case, however, Barney was well aware of Marshall's bathroom problem; he just never mentioned the solution because he's a Jerkass.
In an episode of Two and a Half Men, Jake starts being rude to his mother Judith, having picked up how Alan and Charlie treat Evelyn. Alan proposes that they start treating her with more respect. After Evelyn takes advantage of this and the caterers for the party cause trouble, Charlie, exasperated, says:
Charlie: You wanted that clown to be nice to his mother. Did you ever think to tell him, 'Hey, clown! Be nice to your mother!!' No, we have to throw a party for our crazy-ass mother!
Monk takes this trope to a whole new level. In the final episode, while dying from an unknown poison, Monk finally opens his wife Trudy's final Christmas present, which she had given him just before she died twelve years prior. It turns out to be an "If I Do Not Return" video made by Trudy, and it contains all the information Monk ever needed to find her killer. Not only could the plot of the final episode have been prevented four years before the series began, had Monk solved Trudy's murder almost immediately, he might never have had his breakdown and been kicked off the force. Most of the blame probably lies with Trudy herself unfortunately, for disguising such an important piece of information as a Christmas present instead of leaving it in a lockbox or with their lawyer
The Doctor Who episode "The Beast Below" features the future United Kingdom travelling through space on top of a giant Space Whale. Generation upon generation has come to realise how horridly the whale is being tortured by its harness, and everyone who found out chose to have their memories of this fact erased because it was too horrid to contemplate. In the end, Amy frees the whale from its harness, because she understands that the beast would have consented to carrying the United Kingdom on its back out of sheer kindness all along.
In "Asylum Of The Daleks", if Amy had confided to Rory regarding her fears that she wasn't good enough for him because she couldn't have children after the events of "A Good Man Goes To War", the whole Amy/Rory break-up could have been avoided. Once she admitted the truth, they were more than ready to give their marriage another shot.
Grimm: The shit storm Adalind rains down towards the end of the third season could have been avoided if Nick and Sean had told her about the plan involving her baby. They didn't trust her enough to tell her, but apparently never considered that what they'd have her believe instead would make her a much bigger liability.
Into the Woods: Probably one of the most blatant examples in theater history. When the characters all encounter the Giantess who is looking for the lad Jack who killed her husband, they decide to offer her somebody else as a sacrifice. Unable to figure out what to do, they decide to offer the Narrator. The Narrator reminds them that if he is wiped out, they won't know the outcome of the story. Regardless of this, however, the Witch herself gives the Narrator to the Giantess. Seeing that the Narrator isn't Jack, the Giantess drops the Narrator and he is killed. The Baker's Wife, apparently concerned about how the story will go along without the Narrator, inevitably points out: "We might have thought of something else."
Though a more or less justifiable example would be after the Witch lays a major Reason You Suck Song on Cinderella, Jack, Little Red Riding Hood, and the Baker pointing out what their actions from Act I have gotten them into:
Jack: Maybe I shouldn't have stolen from the Giant.
Little Red Riding Hood: Maybe I shouldn't have strayed from the path.
Cinderella: Maybe I shouldn't have attended the ball.
In The Comedy of Errors, had Antipholus and Dromio of Ephesus asked politely to be let into lunch instead of raging at Dromio of Syracuse and the other servants (granted, it WAS their own house, but still) they'd have run right into Antipholus of Syracuse and the entire twins debacle would have been prevented.
Grendor the Rhynoc, the Big Bad of Spyro: Season of Ice, captures all the fairies in an attempt to reverse the spell he accidentally put on himself. When Spyro defeats him and frees the last fairy, she flat out asks Grendor why he didn't just ask for help, then cures him with a wave of her wand.
A major theme of Rule of Rose. Much of the horrible events could have been avoided if people had communicated with each other properly, or listened to the other party better. Most notably Martha and the police, and Jennifer and Wendy.
In Neverwinter Nights 2, you can speak these words to a warlock who just murdered his own granddaughter, one of your allies, in a fit of rage. The warlock in question is trying to achieve the same thing you are, reforging the Sword of Gith so that the King of Shadows can be defeated, but he's spent the past two chapters trying to kill anyone who might own a shard of the sword, including you.
You can also say this to the githyanki high commander after the boss fight against her. Like the warlock, she too wants the sword reforged so it can be used against the King of Shadows, but is so incensed by a crime she believes you committed against her race that she believes killing you is the only acceptable outcome.
In the final case of Phoenix Wright: Ace Attorney: Trials & Tribulations, Godot admits to Phoenix Wright that if he had warned Wright about the plot to kill Maya from the get-go, they would have avoided all of the drama, to say nothing of the death of Maya's mother. He even admits that he cared more about proving himself to his dead lover, Wright's mentor and Maya's sister Mia, than he did about Maya herself. He basically set up the whole scheme as a way to make up for sleeping through her death due to being in a coma.
Turns up again in Apollo Justice: Ace Attorney; Phoenix was disbarred years ago because a rival tricked him into presenting forged evidence. When he meets the client from that case in the present day said client, Zak Gramarye, reveals he had the real evidence. Phoenix demands to know why the client withheld the evidence, and Zak explains that the evidence, while clearing him, would have gotten his brother indicted in his stead, and Zak was hoping to avoid that.
Batman: Arkham City has a confrontation between Batman and Mister Freeze that was unnecessary, and caused largely by the latter trying to order Bats to do something he would probably do willingly if asked, and the former deciding to jeopardize a potential alliance and risk his own life rather than just swallow his pride for a short while. However, since many people consider the ensuing confrontation to be one of the best Boss Fights in video game history, their stupidity can be forgiven.
In Assassin's Creed: Revelations, Tarik Barleti, the captain of the Sultan's bodyguards, agrees to smuggle weapons on behalf of the Templars so he can learn the location of their hideout and ambush them. The Sultan's grandson Suleiman, unaware of his intentions, suspects him of betraying the Ottoman Empire and orders Ezio to assassinate him. Tarik laments his own hubris with his final words, and Suleiman, upon learning the truth, expresses regret that he was so secretive and chose a terrible way of doing a good thing.
In The Elder Scrolls V: Skyrim, the Civil War was started when Ulfric Stormcloak killed High King Torygg in a duel, which was seen by those opposed to him as murder since he used the Thu'um. However, according to certain characters, not only was the duel somewhat one-sided (considering that Torygg was a young man with limited martial training while Ulfric was a war veteran in his prime), Torygg actually looked up to Ulfric and would likely have declared Skyrim's independence at his urging. However, in Ulfric's mind, he needed to send a strong message to the Empire.
About 80% of the plot of Xenoblade turns on a misunderstanding between the not-Big Bad Egil and the peoples of Bionis writ-large. Egil didn't have a vendetta against them personally, it was their forgotten god Zanza that he had a minor dispute with. It turns out though that Zanza was as much of threat to the peoples of Bionis as he was to the Egil and his people, though it inconceivable to Egil that they would either a) actually stand up to oppose Zanza or b) even have the strength to stand against Zanza in the first place. When Shulk and his friends prove him wrong spectacularly on both fronts he not only admits he was wrong, but makes amends for his horrific crimes in the most literally epic way possible.
In Assassin's Creed: Forsaken, when Charles Lee tries to 'blame' the resurgence of the Colonial Assassins on Haytham Kenway's fathering of their lead member about twenty years before, Haytham answers back that it was actually Charles Lee's mistreatment of the four-year-old RatonhnhakÚ:tonnote Connor Kenway that convinced the boy that Lee — and by extension his associates — were the enemy.
Heck, the entire plot of Assassin's Creed IV: Black Flag kicks off because of Duncan Walpole's inability or unwillingness to 'de-escalate' with Edward Kenway when they wound up stranded on an island in the West Indies, leading to Walpole subsequently being killed when they fought it out, followed by Kenway taking up his Assassin attire, finding the letter from the Governor of Havana offering a reward for Walpole, and deciding to impersonate Walpole.
Spec Ops: The Line is built around this trope. This whole game could've been over if Walker and co. had just completed their recon mission and radioed command. Instead, Walker treated his mission like a America Saves the Day plot, and not only did he doom Dubai, and his teammates, he also destroyed his sanity along the way. The game even chastises the player for continuing to play the game rather than stopping at a certain point. This trope is definitely played for drama.
Tomb Raider (2013): In his long years of being trapped on Yamatai, Mathias is firmly convinced that the only way to stop the storms and escape is to perform the ritual to transfer Himiko's soul into a new body; it never occurs to him that he could have simply destroyed Himiko's body and freed her spirit to do so.
Black Mage: Wait one damn second. Could you have done that at any time?
Sarda: No, not at any time. Don't be so stupid. Just any time I felt like it.
At the end of the Kings War arc of Roommates James, the local hero who even fought a freaking war he didn't want, got confronted with the fact that the Conclave could have stopped the whole thing, but they didn't, they just congratulated the winner and told the loser about her coming punishment. They believe in Written by the Winners you see, so first they wanted to see who wins. This not only means that this arc's plot could have been avoided if they weren't so damn neutral, but also that they will let such things happen again.
The fictional Shark Pool trailer is based around this. There's a shark in the pool. They have no idea how to stop the deaths.
Girl: I can't believe she's dead. How many more people is this thing going to kill?
In the Gummi Bears episode "Duel of the Wizards", a wizard gets ticked off because his magic key was stolen by Duke Igthorn, and he gets in a fight with Zummi and Gruffi. After he finally tells Zummi what he was looking for...
Zummi: If you had just accepted our help when we first offered it, we could have avoided all this trouble.
Wile E. Coyote, trying to capture Bugs Bunny, envisions this trope in action after calmly explaining to Bugs why Bugs stands no chance against a powerful and intelligent predator, when Wile E. wonders why "they always want to do it the hard way!"
The Gargoyles episode "Eye of the Storm" features Odin trying to retrieve the eye of Odin from Goliath. Instead of explaining the situation and asking for it back, Odin leaves Elisa for dead, then tries to steal it before finally trying to kill them all to get it back. If he had just asked Goliath would have returned it, but his actions ensured Goliath would never give it up. Goliath then uses the Eye to stop Odin, and nearly kills everyone. Odin and Goliath then both lament that they could have prevented this if they acted more appropriately.
In "The Ticket Master", after Twilight receives two tickets to the Grand Galloping Gala, all of her friends (and eventually everyone else in Ponyville) attempt to "convince" her to give them the extra ticket. Twilight eventually sends both tickets back to Princess Celestia, saying that if she can't bring all of her friends, then she doesn't want to go either. Celestia's reply is "Why didn't you say so in the first place?", after which she sends extra tickets for all of the mane cast (and Spike).
In "Swarm of the Century", after spotting the parasprites for the first time, Pinkie Pie starts scrambling around town for random musical instruments, without telling anyone else why. The rest of the town has been preoccupied with preparing for Celestia's visit, so they chalk it up to Pinkie being Pinkie. Had Twilight or one of the others stopped Pinkie to ask her about the instruments, they could've avoided the town getting overrun by the parasprites. Twilight acknowledges as much at the end of the episode, once Pinkie's led the parasprites out of town. Hoewever, as Pinkie could have explained why the parasprites were an looming threat and that that was why she was gathering so many seemingly random musical things, this works both ways.
In "A Bird in the Hoof", Fluttershy, being a Friend to All Living Things decides (without asking permission) to look after Princess Celestia's "sick" bird. Fluttershy struggles to nurse the bird back to health, but apparently "fails" as the bird seemingly turns to ashes. It then turns out that the bird is actually a phoenix, afterwhich Fluttershy learns that if she had just asked Celestia first, she would have known ahead of time.
While Spike did try to take steps to prevent a bad outcome, much of "Lesson Zero" could've been avoided had Twilight simply accepted Spike's advice that missing one letter to Celestia wouldn't doom her to Magic Kindergarten. More significantly, Twilight's friends realized that if they had taken Twilight's worries seriously from the start (even if they did think she was blowing things out of proportion) they could've acted to help Twilight and avoid the hilarity that ensued at episode's end.
Queen Chrysalis: It's funny, really. Twilight here was suspicious of my behavior all along. Too bad the rest of you were too caught up in your wedding planning to realize the suspicions were correct!
In the third season episode "One Bad Apple," the whole situation regarding Babs Seed could've been resolved if Apple Bloom and Scootaloo had just listened to Sweetie Belle and told Applejack about it. Applejack tells them this at the end of the episode. However, Applejack falls into this as well. A lot of Babs's behavior made sense to the Cutie Mark Crusaders once she told them about what Babs had gone through in Manehattan. She did, however, explain she intentionally chose not to say anything to avoid getting Babs singled out over things the kid would rather forget.
"Read it and Weep" has Rainbow Dash discover reading while in the hospital, but gets released before she can finish her book. She's fully aware she can simply go to Twilight Sparkle and borrow the book from her. Instead, she launches a nighttime raid on the hospital to steal the book because she doesn't want to admit to enjoying reading like an "egghead."
The Pagemaster: When Richard Tyler, Adventure, Fantasy, and Horror all reach the Exit and meet the Pagemaster, Richard inconclusively berates the Pagemaster for making him go through all the hell he had to go through until the Pagemaster points out that he sent Richard through it all for a purpose: if Richard had been brought to the Exit, let alone gone home, right from the start, he wouldn't have learned how to face his own fears and his friends still wouldn't have been checked out.
An episode of Ewoks named The Haunted Village features the evil Duloks trying to steal some of the Ewoks' soap in order to chase insects away. By mistake they steal a magic one which shaman Logray has developed to hide the food supply from the dragon-like Mantigrue. This not only allows them to cause all sorts of trouble, but also leaves the Ewoks no way to protect their food. Upon learning of the theft, Logray fumes that the he would have shared the regular soap with the Duloks if they'd only just asked.
In He-Man and the Masters of the Universe (2002), a technomancer named Sortek disrupts all the technology on Eternia in order to force He-Man and Skeletor into assisting him with a task. The task turns out to be so trivial that He-Man tells Sortek he would have helped if he'd just asked nicely.
Coon 2: Hindsight features Captain Hindsight, a superhero whose superpower is to instantly being able to tell people how they could have avoided something from happening, even if he wasn't there when it happened.
The season 6 episode "The New Terrence and Phillip Trailer" deals with the boys trying to watch the premiere of the new trailer for the Terrence and Phillip sequel, but Cartman accidentally destroys Stan's TV, leading them to run all over town to try to watch it, only to be thwarted at every place. Throughout the episode, Butters tells them watching it at his house is an impossibility. When they finally ask why after they've exhausted every other option, he tells them it's because his parents aren't home and he doesn't have a babysitter. Furious that there was a TV with no distractions this entire time, they declare they will kill him after they watch the trailer since they have to rush to his house in order to see it.
The Adventure Time episode "Princess Potluck": When Princess Bubblegum forgets to invite him to her party, The Ice King, who is very lonely and pissed off, sabotages it before he asks why she forgot to invite him. It turns out he didn't get his invitation because he never looks at his mail.
Transformers Rescue Bots episode "Rules and Regulations" chief conflict is caused by Chief Burns failing to simply say that Griffin Crest's fallout bunker is protected by an EMP generator that disables all technology, including the Rescue Bots and communicators. Instead, the chief simply orders the bots not to follow him and his son when they go there on a camping expedition. Sure enough when the bots call to check on their status they receive no response, head there themselves, and are promptly immobilized.
You know, we could have avoided all this writing if you just watched the show.