Times where characters realized they "Could Have Avoided This!" in Anime and Manga.
- The 100 Girlfriends Who Really, Really, Really, Really, Really Love You: Near the end of Chapter 11, Rentarou tells Kusuri that she didn't need to drug him to get him to kiss her, her attempt at which led the rest of the girls to get drugged into kissing zombies, which Rentarou and Kusuri spend the next two chapters trying to resolve.
- In Adachi and Shimamura, after the main duo move up a year, Shimamura ends up meeting and talking with a few classmates. While Shimamura doesn't really care about those girls, to the point at which she can't even clearly remember their names, Adachi becomes depressed and spends days angsting about the state of their relationship, and whether Shimamura cares for her. Eventually, Adachi realizes that if she'd just talked to Shimamura, the entire misunderstanding would have been cleared up.
- Berserk: The King of Midland realizes this as part of his Dying Dream. He realized that he didn't want to be king anymore, seeing his position as restrictive and leaving him lonely and isolated, and had a perfect chance to abdicate his position and have Griffith take over the throne as his daughter Charlotte's husband — and he was on the best way of doing so during the Golden Age arc. But then he found out that Griffith had slept with Charlotte, and made the king realize that he was lusting after his own daughter, which shattered his world-view and focus the rest of his time on seeking revenge against Griffith. He realized that, had he kept his temper and not succumb to petty feelings of jealousy and revenge, he could have been free of his position and enjoy the rest of his life with a happy daughter and a peaceful kingdom.
- Bleach: In one of the anime's Filler episodes, Yumichika, Hanatarou, and Rin have to make a cake for a deceased patissier's mother, who died before his mother could ever taste one of his recipes. Since he's a ghost who cannot be seen by ordinary people, they have to make the cake and present it to his mother for him. Being Soul Reapers, they don't even know what cake is so are appalling chefs who take the entire episode to produce an edible cake. At the start of the episode, Rin is working with a device that reveals spirits, but it's only at the end of the episode that the device accidentally reveals the chef's ghost to his mother, allowing him to communicate directly with her. In The Stinger, Yumichika irritably points out that they could have done this at the very beginning, thus negating the entire episode.
- Cells at Work!: The allergy plot is a subversion. As the plot ends, the character realizes that the whole turmoil and disaster was caused by them overreacting to a mostly harmless allergen. However, the characters are cast of anthropomorphized cells, and since an allergy is your body overreacting to something, White Blood Cell comes to the conclusion that even knowing this, they wouldn't be able to stop it, since they are doing their job the way they should and it is the only thing they can do, much like your body can't decide to not overreact to an allergen.
- A Certain Scientific Railgun:
- The first major villain's machinations led to a bunch of kids landing in comas, connecting them in a psychic network that she uses to gain several superpowers at once. It's ultimately revealed that she did this in order to gather the supercomputer-level processing power needed to figure out how to save a bunch of other kids that have been in comas since a past tragedy. Subverted in that while the heroes essentially call her out on the fact that she wasn't open about such an altruistic motive, she counters that she did try the easy way first. Dozens of times, in fact. This scheme was actually the last resort after the administration of the city continued to block her at every turn.
- During the School 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. As Mikoto angrily points out, 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 Misaki's telepathy, and Misaki is far too paranoid to work with someone she can't mind-read.Misaki: What if you had decided to betray me? What if you had used the opportunity to gain the advantage? What if you didn't care about them at all, and I had tipped my hand?
- In the first season of Date A Live, Kotori's date, which took place in Episodes 11 and 12 could have been avoided completely. Reine tells Shido at the end of Episode 12 after he successfully seals her that her love meter was already maxed out back when he talked to her in the isolation room and could have sealed her right then and there. However, she tells him that Kotori had her keep it secret so she could go on a date with him anyway. Kotori then claims Reine was lying, and that the readings were wrong, then bribes her with a dessert. Reine then states the readings were off. For his part, Shido says he loves her... as a sister, which prompts Kotori to kick him as a result.
- Dragon Ball Z:
- Assuming Goku couldn't handle Majin Buu after witnessing what he assumes to be Goku's full power, Vegeta sucker punches him and goes to do it himself. It ends disastrously and Vegeta is forced to blow himself up to kill Buu, which still fails. Later, Vegeta and Goku argue over this with Goku calling out Vegeta for his pointless self-destruct and Vegeta blasting Goku for concealing Super Saiyan 3 from him, motivating his reckless decision.
- Gotenks hides his ability to transform into Super Saiyan 3 from Piccolo and fakes losing to Super Buu, wanting to reveal the form dramatically before winning the day. Before he can get that far, Piccolo blows up the door to the Hyperbolic Time Chamber, imprisoning them with Buu until the latter manages to escape. Gotenks tries to put the blame on Piccolo, accusing him of jumping the gun, but Piccolo turns it back on him and chews him out for making a game of the battle.
- In HappinessCharge 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.
- One episode of Hell Girl features a girl who takes in a stray cat and is promptly harassed 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 Hitoribocchi no OO Seikatsu, a benign example happens in Mayo's arc. Bocchi is worried about a possible class shuffle undoing her efforts to befriend her entire class (since the friends she's made could end up in different classes next year), and tries to stop that from happening. Bocchi eventually finds out that the school doesn't shuffle classes around after Mayo confesses that she asked about it, so she had nothing to worry about. That said, her efforts helped Bocchi befriend Mayo and put her one step closer to her goal, so it's not as though it was a complete waste of time.
- 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."
- In K, after Mikoto kills the Colorless King and Shiro, his Sword of Damocles starts to plummet, forcing Reisi to kill him before the destruction would kill thousands of innocent people. Reisi bitterly says this could have been avoided if Mikoto wasn't consumed with Revenge Before Reason and took action to prevent this earlier.
- In The Legend of Zelda: Twilight Princess (2016), Darpa is furious to discover that Link is able to instantly restore their displaced hometown simply by entering the Twilight Realm through the Mirror of Twilight—an artifact located within walking distance of both the town's original location and present one—and pulling the Gaurof Sword from its pedestal again.
- In the second season of Lyrical Nanoha, the Wolkenritter assume that stealing others' magical powers is the only way to save their master. That's obviously wrong but they don't realize that until the late episodes, joining forces with the heroes. Generally, Nanoha herself believes that everything can be avoided and always inquires about the baddies' motivation (usually, to no avail) before befriending them into submission.
- 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 Magic of Stella, after Yumine saves Tamaki from what they believe to be a sex-crazed Kayo, Tamaki realizes that when Kayo refers to her babies, she probably means her compositions, and that the whole thing was a misunderstanding.
- In My Hero Academia, Twice's Quirk allows him to create clones of himself that fade away if they suffer injuries equivalent to a broken bone. After an incident in which his clones started killing each other, the original Twice becomes traumatized and wonders if he is, in fact, a clone. During the Meta Liberation Army arc, one member of the eponymous vilain organization breaks Twice's arm, causing him to realize that he is the original and not a clone. Twice admits to himself that he could have hurt himself at any time to test whether he was a clone, but didn't because he was scared that he'd end up fading away.
- In One Piece, in order to reach Skypiea, the Straw Hats had to track down and ride this massive geyser that can shoot whole islands into the sky. After getting to the White Sea, Ganfor tells them that there are other ways to reach the Sky Islands, and is stunned that the Straw Hats rode the Knock-Up Stream, as it's an All-Or-Nothing shot. Nami goes ballistic on Luffy at the idea that there were safer ways of reaching Skypiea. Subverted as according to Gan Fall, while there are other ways to reach Skypiea, they involve sacrificing crew members, which the Straw Hats refuse to do. He also mentions that those who survive the journey through the Knock-Up Stream are viewed as brave and highly skilled, particularly their navigators. The Straw Hat Pirates are an excellent example of this, eventually earning them the respect and aid of Gan Fall.
- Episode 7 of Pokémon: To Be a Pokémon Master revolved around Ash, Brock, and Misty rescuing a trapped Wailord. After spending the entire episode concocting an elaborate pulley with an Enemy Mine alongside Team Rocket to boot, Misty realizes at the very end that this could have been over in seconds if they just put it in a Poké Ball. Ash replies that the important thing is that they had fun.
- Poison Berry in My Brain: For most of Chapter 7, Ichiko stews over whether or not to leave a note at Saotome's door. When he finally opens up again, he points out that she could've just sent him a text since his number is in the caller history on her phone.No one thought of that...
- Sleepy Princess in the Demon Castle: The conflict of one chapter involves the Princess getting a cavity, and the demons being unable to treat it because she refuses to let any of them (except the teddy demons, none of whom are dentists) look into her mouth. It takes hours of fighting and a needlessly complicated workaround (the dentists being blindfolded while the teddy demons guide them through the procedure) to finally treat her, and it's only afterwards that they realize they could've just used magic to make her fall asleep and treated the cavity without any trouble.
- In Space Battleship 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...
- In Space Battleship Yamato 2199 the human characters realize at some point that the war could have been avoided had one of their ships not opened fire without provocation at first contact, and the whole devastation of Earth could have been avoided by simply surrendering (in fact a number of Gamilas characters openly wonder why they don't just surrender).
- In Strawberry 100% Yui at one point forgets a notebook at the home of her childhood friend Manaka, who has to bring it to her school... A One-Gender School with a guard at the gate, prompting him to sneak in to put the notebook on her desk only to get in serious trouble when he's spotted. His friend Tsukasa, who goes to the same school, helps him escape... And then asks him why didn't he just give the notebook to the guard.
- Super Dimension Fortress Macross: Spoken about in the first episode. After the Macross automatically fires upon the Zentradei when they arrive in the Solar System, Captain Global immediately realizes the ship was booby trapped to do so. He laments humanity overlooked this fail safe and the Earth was doomed to an inevitable war. Unbeknownst to humanity at the time, the Zentradei didn't arrive to attack or invade Earth. They were just looking for the Supervision Army warship that was rebuilt into the Macross, and wanted to avoid fighting an "inferior species" unrelated to them. That all changed after the two Zentradei scout ships were destroyed by the Macross. Though Britai and Exsedol eventually figured out the Supervision Army warship was rebuilt by humans several minutes later, they couldn't let Earth get away with attacking them first. Thus the first Earth-Zentradei War began.
- In the Tales of Eternia anime, Marone refuses to give the party a lift off the island, which makes Farah get upset at her, which leads to the two fighting, which leads to a swimming contest, which leads to a sea monster attack. Turns out Marone had a very good reason for saying no, her drake was injured and needed time to recover before flying such a great distance. Farah points out she should have just explained herself, then all the drama could have been avoided.
- In Chapter 13 of We Never Learn, Uruka realizes too late that not only did she forget to wear a bra to school, she did so on the day a sports tournament was being held. Only on the last panel of a chapter full of awkward physical activity does Uruka, a star swimmer, realize she could have just worn her swimsuit as a substitute.
- 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!Neo 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.
- Yu-Gi-Oh! ARC-V: Subverted. After Kurosaki hospitalizes Sora, Yuya, Yuzu and Gongenzaka gather up to discuss away from everyone else what they know about their background. When Yuzu brings up that Kurosaki and a friend of his were behind the mysterious attacks on LDS, Gongenzaka angrily asks her why she never said that she knew who the culrpit was, because if she had the LDS would never falsely accuse Yuya and they wouldn't have tried to take over and buy out You Show Duel School. At this point Yuya figures out that the reason Yuzu said nothing is that he and the other culprit are Identical Strangers. Yuzu confirms this, saying that at first she thought that it was Yuya in disguise, but she was confused because he would never do that. By the time the misunderstanding was solved the whole business with LDS had passed.
