Some kinds of Video Games really can't get away with these, as they can cause brutal Gameplay and Story Segregation, but developers try anyway. If the player character is the idiot, see Stupidity Is the Only Option. Plot-essential NPC stupidity can go here. note However; at the same time, doing something that's Too Dumb to Live is usually given a game-over scenario.
Other kinds of games thrive in this scenario, especially action games. Why is it Up To You? Because you're the only character or team with any intelligence and skill related to adventuring (or whatever the game is about).
The Ace Attorney series is really guilty of this (pun unintended). Most of the time your clients are in a pickle because they won't talk.
In Case 1-5, Lana Skye is extremely uncooperative because she's afraid that if she talks, Gant will have her sister arrested for murdering Neil Marshall. Just as the protagonists try to get her to crack... Gant pops into the court room and makes a very thinly-veiled threat towards her and no mention is made of this by anyone. Granted, the people in charge of fixing things up have already figured out what's going on, but you'd think even the Judge would be clued in. (Given how tightly the Judge holds onto the Idiot Ball though...) That's not even mentioning how the frame-up for Ema Skye revolves entirely around everyone buying that a scared fourteen-year-old hit a grown man hard enough to knock him upward and with enough force to be impaled and remain hanging on a decorative sword. note Actually the real deal, as noted by Phoenix earlier And that said grown man somehow focused more on writing Ema's name in blood on a vase (which somehow flew into his arms supposedly from the force of the impact), instead of trying to do something about the life-threatening injuries he'd have acquired.
There is a case where the protagonist must figure out how a magic trick is performed, not because it has any relevance to the case but simply because the judge wants to know. Despite the fact that everyone else in the courtroom has figured it out, including your client and your assistant, no-one will help because "you can't tell a magician's trick". One of the witnesses, at least, had the excuse that she was under contract to keep the trick a secret, along with hiding the fact that she was blind.. One would think that her employers would make an exception for her standing witness for a murder trial, but apparently not.
The case of the prosecution rests on the idea that a frail, fourteen-year-old pianist with no firearms training could fire a 45-caliber pistol without injury, despite the fact that it is constantly stated that the recoil would be enough to dislocate the arm of a grown man of average build. (This is given a minor Hand Wave early on; the only reason such a flimsy case is going on trial is because the Borginian Embassy is pressing for a swift resolution to the case—an in-universe case of Executive Meddling. Likely someone in the Borginian government knew about the cocoon smuggling going on, and that the murder victim, Romein LeTouse, was investigating it.)
Gumshoe in Ace Attorney Investigations Case 4 gives false testimony and implicates himself because he refuses to admit that he shared a Swiss roll with the young Kay Faraday, who broke her promise never to take anything from strangers. He only cracks when Edgeworth not only deduces the entire sequence, but also the reason he wouldn't spill.
The modern version had an idiot plot, that only revealed itself to be an idiot plot at the end. It turns out the Distressed Damsel is really an imprisoned demon queen and the Druids did not warn The Bard that he was being manipulated to unleash a great evil (not that it would be the first time the Bard did it). If anyone stopped to explain anything, then well, there goes the whole game.
And that the cute little dog that the Bard adopted wouldn't have been killed in the game's major Kick the Dog moment.
And with the kind of things he does pull while conscious of his actions, Finstown and the Nuckelavee for example, one could argue that he'd make things worse, or possibly just go through with it anyway since you'll find that the evil ending is one sweet deal for the bard, while being good gets him nothing. The bard is a self-serving liar and crook, hardly a hero in any case.
Near the end of Bravely Default, the story starts veering into this territory. This is primarily because as Ringabell regains his memories, he remembers Airy killing the party. Throughout the story, it's clear through conversation that Ringabell doesn't trust her anymore, and for good reason. He even tells this to Tiz. There's also the fact that, as noted by Ringabell in D's Journal, the party has eventually caught on to the fact that each time they enter the Holy Pillar in one world, they're creating the Great Chasm in the next. So with all of this knowledge, you'd think that they'd kill Airy where she stands, or at least stop awakening all of the crystals. Do they do any of that? Nope. They just continue awakening the crystals, then are shocked, shocked!, that Airy really WAS evil. The game attempts to Hand Wave this by saying that Ringabell was too "afraid" to take action, but not only is that a bullshit excuse, even if he really was afraid, he should've known that continuing down this path would eventually result in the party's death, specifically Edea's, and that would put his priorities in order.
This is a player induced idiot plot. You have the option to undo Airy's evil plan at any point after chapter 5 you choose to. If you keep picking up damning evidence against her while still following her plan you only have yourself to blame. Even choosing to end the plot mid way through will add on the characters commenting on the evidence you've gathered so far and how it convinced them to take action saying that the characters are fully aware of the situation, but how and when they act on it is the player's choice.
Much of the conflict from Sonic Adventure 2 comes from the fact that people can't tell Shadow and Sonic apart. Although the two are fast, the same height, and share similar facial features, their color patterns are vastly different (Sonic is blue, Shadow is black and red, and the two aren't mirror images of each other, such as Shadow's chest hair vs Sonic's stomach) and their spines are shaped differently, making it very easy to see the difference between the two, and Shadow is clearly seen on a news report that Robotnik is watching.
To make matters worse, while it could potentially be handwaved that Shadow was primarily seen by officials at night where the blue/black difference would be harder to notice, at one point Amy mistakes the back of Shadow for Sonic in broad daylight and close up where the difference is VERY apparent.
Amy also makes a similar mistake with Silver in Sonic the Hedgehog (2006) when she spots him and immediately pounces on him, thinking he is Sonic and then realizing that he isn't. Silver is an (obviously) silver colored hedgehog. Sonic is a blue hedgehog. You'd have to be blind to mistake the quills, too; Sonic's quills point straight back, while Silver has five that point straight up and to the side to form an arc around his head.
Also the majority of Knuckles the Echidna's appearances after his debut in Sonic The Hedgehog 3/ Sonic and Knuckles count for this considering that he learned that Eggman only befriended Knuckles initially so he would fight Sonic, while Eggman stole the Master Emerald, and yet Eggman manages to trick Knuckles in almost every other game to fight or somehow slow down Sonic due to Knuckles being so gullible.
Shadow Mario looks like he's made of dark blue water, while Mario is Caucasian with a red shirt and hat (although the overalls are blue).
Of course, even worse is the fact that Mario wasn't even on the island when the crimes he's accused of were committed, and there were numerous witnesses right there who could attest to that. Considering that during the trial, you see a movie with Shadow Mario committing numerous crimes which proves he looks nothing like the regular Mario, and this whole scenario literally hits They Just Didn't Care territory.
Add in to Super Mario Sunshine that the point of the game is that the inhabitants of the Isle Delfino are in a panic because of the disappearance of their Shine Spirites...and a good chunk of said Shine Sprites are in the possession of said island inhabitants. If the various people would just give Mario the damned Sprites instead of making him win the watermelon contest or bringing them a pinapple or breaking all of the crates in the room, or forking over blue coins, the game would be over a lot faster.
Then there are the repeating segments where Mario fights Shadow Mario. That's right, they're seen in the same place at the same time, and no one thinks they may not be the same person after all. Insert four-letter words here.....
Basically the entire plot of Sonic the Hedgehog (2006), which depends heavily on the characters taking every single bit of information given by known villains at face value, a completely helpless princess getting repeatedly snatched away by the same exact villain within minuscule time intervals, and everybody completely failing to comprehend the potential applications of their ability to time travel at will.
The plot of the original Sonic Riders begins with Dr. Eggman appearing on public TV screens worldwide, announcing he's holding some races where entrants need to give him a Chaos Emerald. In what can only be explained as this, Eggman manages to get all seven of these all-powerful jewels, one of them from Sonic himself, in this manner.
Another really good example is Tales of the Abyss. A very large portion of the plot can be credited to most, if not everyone involved being either hypocritical, self-centered and short sighted, or astonishingly stupid.
The game is basically a Deconstruction of this - Luke is a complete idiot for the first part of the game, and the characters get pissed off at him for it, and he only stops when thousands of people die because he thought he could solve everything with his hyperresonance. The explanation being that Luke literally has a mind that's only 7 years old. The characters are pissed off at him because he acts 7 but appears to be in his late teens so he comes off like a complete jerkass. It's after he's gone too far that be begins to mature into a more sensible person and the party eventually learns about his full situation and become more patient with him.
9 Dr. Wily, the villain for the last 9 games, appears on TV to declare that Dr. Light, the man who helped put him away the last 8 times, is the true villain. He then goes on to ask for money to be transferred into his Swiss Bank Account, so that he can fight Dr. Light himself. For some reason, a planet full of idiots falls for this, and Dr. Light is arrested.
Many robots are infected by a computer virus that makes robots violent. No one is able to make a cure because humanity doesn't have the support that robots provide. No one, not even Dr. friggin' Light himself, decides to either just cut their losses, back up as much data as possible, and reset the robots to factory settings to purge the virus. Hell, this game points out how stupid humanity is since they followed Dr. Light's example and made the robots that friggin' complicated in the first place.
10 also gets a special notice in that it's the third time Dr. Wily has gotten something of his to Dr. Light's lab. The first was when Dark Man kidnapped Dr. Light in 5's intro. The second time was Bass infiltrating Light's lab in 7 so he could steal Mega Man's Rush Adapter. Instead of piloting his flying saucer himself Dr. Wily could've flown it by remote with a bomb inside and turned Mega Man into a crater. Heck, just shooting Dr. Light at any point in 5 would've saved Wily so much trouble.
This is actually subverted if you've seen the ending to Mega Man 7 where Mega Man is so pissed at Wily that he points his blaster at him, and prepares to fire a fully charged shot to kill Wily and end his evil once and for all. Mega Man stops at the last moment and spares him because Dr. Light told him to never harm humans no matter what. Wily needs Light out of the way while his does his evil deeds, but not dead because he once worked with Light and knew the potential of the robots and what they might do if pushed hard enough, which means his decision to keep Light alive makes a lot more sense. Wily's just a guy who likes Tempting Fate, and this carries on into the Mega Man X series.
Every Mega Man game is full of idiots. In Mega Man X, humans actually thought it was a good idea to build robots with free will, without taking any time to test their morality as X was, then give them a massive amount of built-in weapons, and then keep producing them till they outnumber humans. And later on, they make them godlike by giving them copychips, which allow them to transform into anyone else. And, of all people, they put the thoughts of the main villain Sigma into the chips.
In every sequel people anyone seem to forget that Lan saved the world in the previous game(s), which makes for a bunch of dialogue of how he is just an ordinary kid or how inexperienced he is to fight this time.
The update theory would then lead to the implication that Lan get updates that would debilitate Megaman without gathering helpful available equipment beforehand (buying updated chips to use after the update rather than having near nothing) and without actually knowing how to use them (still needing to be taught basic battle techniques).
Although there might be some reasonable explanations for chips, such as Lan selling them to help pay for damages caused or them becoming useless, let's not forget the people. Good freaking Bass, those people can be idiots. Now, for the most part it's slightly characteristic, people learn about navis and netbattle and whatever other hobbies and don't learn about extensive stuff, but that doesn't excuse some of the reasons for plot events. Let's start with the most obvious one: Mr. Match. In one game out of all them that he's actually honest, the last one, the rest of them he's still working against Lan. In the third one Sci Lab, after having already witnessed his crimes, actually put him on as a scientist there. After he's already tried to cripple the world twice before.
Many of the Story Arcs in City of Heroes, especially when Nemesis gets involved. A lot of it involves blatantly misplaced trust in blatantly villainous organizations with proven track records. None of it quite compares to the free comic books involving the Freedom Phalanx, however. They are depicted as total caricatures of their in-game selves, completely incompetent to a level that makes one wonder how they could have become the premier superhero group. They also get defeated by opponents that, in-game, would just go squish in a single attack from them. It has to be seen to be believed. It still bothers a majority of the players that these comics are, sadly, canon.
The Dungeons & Dragons computer game Death Knights of Krynn featured a stunning moment of idiot plot. For most of the game, the party have been accompanied by Sir Durfey, a veteran knight and expert undead hunter. Bear the latter in mind. During the penultimate dungeon (an evil tower in this middle of undead-infested countryside), the party rescues Lenore, a (very large and muscular) serving girl who is blatantly Kitiara (minion of the Arch-boss) in disguise. Durfey immediately volunteers to leave the party and escort her home on his own. Repeat: The expert undead hunter wants to lead the thinly disguised henchwoman home through undead country. He leaves (the player can't control this; he will leave the party regardless) and is, unsurprisingly, ambushed by the undead, killed and bought back as a zombie to fight the party. Note that he's only two rooms ahead of the room that he left from. That's right, he was killed, bought back as a zombie and positioned with an army of minions to fight the players in the time it takes to cross two rooms. Imagine a Necromancer Nascar Pit Crew. Able to zombify a person in 12 seconds.
Made especially egregious when you realize it's an action-adventure remake of Mortal Kombat II, where our heroes aren't nearly as moronic. Whereas our heroes' foolish actions in MK2 is forgivable due to their unfamiliarity with Outworld and distractions of other important things (like taking revenge for the death of an entire shrine or rescuing a fallen comrade), Shaolin Monks everyone are so brick-stupid as to fall for a Gambit Pileup that could've only succeeded if they weren't smart or perceptive enough to realize their "friends" are not themselves. Well...Johnny Cage retained enough Genre Savvy to realize what was going on, but his keen insight unfortunately didn't rub off on anyone else.
In particular is the fact that "Raiden" makes a big point of the fact that Shang Tsung grows more powerful the more people die and yet sends Liu Kang and Kung Lao to go kill a bunch of powerful warriors - that should have been a huge red flag on its own when dealing with a shapeshifter, but it gets even dumber when you consider how often he got angry at the two for asking any questions whatsoever and actively worked to turn them against each other.
Albert Wesker in the original Resident Evil, despite being an alleged genius, throws a couple of three-pointers with the idiot ball. He blackmails Barry (in Jill's game) and decides to gloat evilly about his plan when he could have very easily just unleashed the Tyrant and let it kill them. Then when he finally gets down to releasing it, he decides it is a good idea to stand right beside the untested experimental monster and just hope that it doesn't decide to kill him as well. At least the Re MakeRet-Conned it so being impaled was part of his master plan, but still...
In his spectacular Let's Play, The Dark Id takes colossal fuck-up Steve Burnside to task - noting that the game is significantly longer due solely to his screwing up...
He refuses to hand over gold-plated guns needed to open a door unless you can give him "something fully automatic" - which sends you on a wholly unnecessary Fetch Quest.
Not to mention, taking those gold-plated guns triggered a death trap. When Claire did it, she was smart enough to put them back and escape. Steve is too stupid to figure this out and requires you to save him. After that, he still won't give up the guns!
When he has an opportunity to shoot the unarmed villain, he completely freezes up because it turns out said villain is a transvestite (at least, that's what it looks like; he has a good thirty seconds to pump the guy full of lead and doesn't). This gives him time to set the self-destruct system and force you to go to Antarctica when you do escape.
While trying to escape Antarctica, Steve screws up operating a crane and flooding the room you're in with poison gas. Because (ready for this?) he's too busy staring at the player character's butt.
Clock Tower 3. Alyssa gets a message from her mother which amounts to "Whatever you do, don't come home for your fifteenth birthday." Go ahead and take a guess what she does. When she arrives, an obese cadaver-looking man hints that he's killed her mother and basically threatens to rape her. Her reaction? "I have to save Mum!" Later, when the Big Bad is revealed, things get ever more idiotic, such as Alyssa's grandfather's name apparently being Dick. Not Richard. Dick. Someone actually named their son Dick Brown. And this leads him to believe in a totally ridiculous set of myths which require him murdering his granddaughter with no real hope of reward. The Dark Id has quite a lot to say about this one too. Mostly invectives.
It gets worse when combined with the fact that it is made clear very early in the game that this totally ridiculous set of myths requires exact timing to work as intended. TDI accurately summed the plot up about five updates from the end of his LP as thus:
"The bad guys are making no effort to chase Alyssa. She can literally just walk out the front door and be done with things. She can thwart the entire evil plan of her grandfather by just hanging out in an arcade playing Street Fighter 3 for the duration of her birthday.
The entire plot hinges on Alyssa being too fucking stupid to just leave."
Valkyria Chronicles: Almost every problem in the second half of the game that isn't strictly the war itself could have been easily solved by someone, anyone, looking at Alicia's Valkyria abilities and the effects they would have on her from an objective standpoint, instead of making assumptions based on the bad example set by Selvaria and her first traumatic power eruption. Welkin only manages to come close by tying it in with his love confession, and of course this only happens at the most dramatic moment possible rather than taking her aside to reassure her when she first expressed how overwhelmed she was. By the time she decided to attempt the Suicide Attack on the Marmotah, Alicia had clearly gained control over her new abilities, and could use them as much or as little as she chose. Everyone could have avoided a lot of trouble if someone had just pointed that out early on and attended to her emotional state for five minutes, instead of Welkin waiting until the last minute while everyone else ignored her repeated cries for help.
It could all have been avoided if either of the Valkyria had realized that the reason they're so prized as warriors is because they're the most devastatingly powerful creatures in the known world. If either of them had stood their ground and said "No," there wouldn't have been a damn thing anybody could do about it.
In The Legend of Dragoon the major town in the second act has a castle under generally heavy guard. The chapter would be SO much easier if the king in your party would just come right out and say, "I'm King Albert, here's my proof, and I can vouch for these people." But he never does. Oddly enough he even comes right out and says he will not bring up his royalty to get around, despite the rather massive stakes.
Mario & Luigi: Bowser's Inside Story. The game would be much, much shorter if everyone wasn't busy eating dangerous types of mushrooms given out by a stranger who happens to be Fawful. In games when he isn't the Big Bad (and sometimes even then) Bowser's always portrayed as a bit of a moron and ends up as the Butt Monkey.
Bowser: “TOO MANY WORDS.”
The Elder Scrolls III: Morrowind expansion, Tribunal. It would take too long to explain everything, but to summarise it involves taking orders from somebody who admitted to trying to kill you (multiple times), switching sides for no adequately explained reason (multiple times), and never questioning why somebody needs these immensely dangerous artifacts that you're grabbing. Oh, and terrorising an entire city, for entirely "benevolent" reasons.
The Crowning Moment of Stupidity comes when one of your party members blows himself up for absolutely no reason whatsoever.
The above example only hints with what's really wrong with FF4: the game's tendency to make too many of its heroes commit acts of self-sacrifice, simply to shuffle new characters into the mix. With Tellah (who died trying to summon meteor to kill Golbez) and The Black/White Mage twins (who turned into stone to stop moving walls from crushing the heroes), those acts made sense. But when later characters do the same thing with increasingly arbitrary methods, players have a very hard time suspending disbelief. Exactly how does a monk with no experience with technology manage to stop an exploding computer, or how does a mechanic bombing the entrance to a world seal it away? To make the entire thing even dumber, with the exception of Tellah, all of the dead heroes came back, having survived their near-death experiences.
Also, the MacGuffin the villain needs is behind a magically sealed door. The only item that can open the door is in the hero's possession. Upon seeing that the Magic door has, in fact, not been opened, the heroes decide, for no adequately explained reason, to open said door and go get the MacGuffin, despite the fact it is of no use to them - only to the villain. Rather than say drop the door's key into the many, many lava pools all around the cave. To make it even dumber, they bring someone who has repeatedly been mind controlled by the Big Bad, having shown himself to be very vulnerable to this. The Nintendo DS remake makes it even more stupid by having said frequent mind control victim realize the villain is about to take him over the moment he enters the cave, thinking to himself: "This feeling...I've felt it before..." then, "No...no! Not again!" but not warn any of his fellows before the villain's assumed control of him as they stand in front of the aforementioned MacGuffin. It's specifically mentioned by the Dwarf King that the seal is not impenetrable, and that it would only be a matter of time before the villain could force it. The plans were to steal the other 7 Mac Guffins back before he got the 8th one, and when that failed, to get the 8th MacGuffin and move it somewhere else, hopefully before the villain realizes it's been moved. Clearly, this does not work, but the plan isn't as stupid as it sounds.
Worse still after having defeated the main antagonist in battle right before he can steal one of the last Mac Guffins, they just turn around and walk out leaving him on the floor where he promptly gets up, takes the MacGuffin and warps away. Seriously. Particularly baffling considering the fact that it's a plot point that the main antagonist is out trying to get one of the Mac Guffins when they assault his tower. They easily could have just repelled him the first time only for him to come back and steal it when they were busy storming his tower. Would certainly make a lot more sense then just ignoring him after his defeat.
Very rarely does anyone find the teams suspicious, even when they're clearly stealing things (like Teams Magma and Aqua, who are so obvious that it's almost painful). It's never explained why few people other than some ten-year-old Pokémon trainer ever bother to do anything in a world that is full of people who have been using Pokémon for much longer. It's understandable that apparently said ten-year-old is apparently a prodigy (since all other Champions are at least five years older), but someone other than Lance, Cynthia, Looker, and Steven should have at least noticed.
The Forbidden Land of Orre is a bit of a mixed bag. Sure, the police are bloody failures, but Cipher heeds the First Rule of Warfare - "don't let the enemy know what you don't want them to know". The only way the player character (a rogue Snagem goon in the first game, a prodigal agent in the second) can learn anything is to engage Cipher firsthand, and everyone else is left in the dark. As one troper said, a Plasma Grunt said that Teams Rocket and Galactic failed because they were too overt; Cipher would be a dream team for them.
In the first games, a house was robbed, footprints and destroyed furniture are everywhere and there is a human-sized hole in the wall. At least 3 officers are in- or outside the house. But guess what? The Obviously Evil thief is less than 10 meters away from the house, rummaging through his stuff and only a 10 year old kid notices.
To give one a view of the tree of lack of communication that keeps the plot going: Aqua immediately believes Maleficent's claim that Terra removed Aurora's heart, even though the person telling her that is, well, Maleficentnote that was only very partially true. Terra, we should note, believes in just about every Disney villain he comes across (save one or two exceptions), and has his journey driven by the words of Master Xehanort. You could say he isn't guilty of trusting Xehanort, and that is true, since Eraqus didn't give him any reason to not do so... but he should have; Eraqus for whatever reason never seems to mention that Xehanort kind of tried to commit genocide for shits and giggles, instead opting for presenting him to his pupils as a righteous, good Master. The plot moves along because the good guys never, ever seem to stop and tell each other why they are doing what they're doing, or what have they found out about their particular quests, which increasingly accumulates doubt and grievances among them. Predictably, it doesn't end well for any of them.
Bully. At least during chapter one, Gary was giving Jimmy a couple good reasons to trust him and didn't openly stab him in the back until the end of Chapter one. However; had Jimmy simply looked for Gary to get revenge instead of trying to get the other cliques to respect him in chapter two, he could have avoided most of the game.
None of the game would have happened if Crabblesnitch himself weren't a useless moron from the beginning, but that's pretty much the point of his character.
Saints Row: The Third. The first two games were intentionally over the top, but at least things made sense in the bizarre world where police reality shows involve chainsaws and gang conflicts are solved with radioactive waste. The third game does away with realism altogether and relies on every NPC being an idiot.
At one point the military gets involved. They occupy the city, erecting roadblocks and conducting a large scale search of the city to find you. Where are you? Maybe at the wheel of the luxury car that is blatantly painted in Saints gang colours. Or maybe in one of the obvious strongholds with the obvious fleur de lis logo on them. The only anonymous stronghold is the one that actually gets attacked.
Luigi's Mansion: If Mario and Luigi didn't think Luigi had won a mansion in a lottery he didn't even enter, then there'd be no game. Or if Mario hadn't walked straight into said haunted mansion rather than waiting for Luigi to arrive. Or if Luigi didn't end up releasing the Boos and King Boo by pressing the ominous red button in the store room... Basically, the whole game wouldn't have happened if the Mario Bros didn't buy straight into the fantasy version of your average lottery scam.
On the other hand, it's mentioned that Mario went ahead to the mansion to see if it was legit (possibly even seeing that their winning the mansion without entering the contest was suspicious and that something was obviously wrong) and was captured because he wasn't expecting himself to be effectively defenseless against the ghostly enemies. Luigi's freeing the Boos is more of an example of Stupidity Is the Only Option, since they drop the key to the next area, without which you'll never be able to progress and therefore never rescue Mario.
This game plays with the trope fairly well considering that even the Big Bad King Boo lampshades it.
King Boo: "What do they feed you Mario Bros. anyway? Gullible Soup?!"
The iPhone game The Secret of Chateau de Moreau has this. The entire game revolves around the main character trying to prove his own innocence after his stepfather died and left his entire will to him instead of his actual children. Normally, this would be understandable, but the main character was at a boarding school when his stepfather was killed and didn't even have any means to kill his stepfather. The entire game could've been prevented if they just tried to put two and two together and realize the main character couldn't kill someone far away without any means to so much as contact him aside from mail.
Played for Laughs in Conkers Bad Fur Day. It takes the Panther King and Ze Professor a ridiculous amount of time to realize the reason why the king keeps spilling his milk; the table he rests it on is quite obviously missing a leg. This is also pretty much the only reason Conker becomes involved with them and the game turns out the way it does; Ze Professor determines the best solution is to find and capture a red squirrel to replace the missing leg, using far more resources than would have been needed to just buy the king a new end table. Or fix the leg using the duct tape.
The plot of Ace Combat 5: The Unsung War can be split about evenly into three parts of about equal length, but not equal intelligence. The gist of the first portion is: Enemy planes open fire on your country for no reason, sparking a war when you dare to defend yourself. At some point, the President of Osea is attacked while trying to hold talks with the other nation's leader to end the war, and is left to be rescued by a squad called the 8492nd. Two missions later after the war unexpectedly escalates, the player's squad overhears the 8492nd attack a civilian complex to spur the enemy further on. The player's squad is promptly blamed for the attack, since the 8492nd apparently doesn't exist and the attack was where the player's squad was supposed to be operating. This angle is dropped for a bit (other than every other briefing ending with your commanding officer telling you, basically, "if you really are innocent prove it by slaughtering more Yukes"), up until the second part of the story starts - the apparently-nonexistent 8492nd comes up again and accuses the player's squadron of being traitors. Rather than question what the player did or why the squadron that apparently doesn't exist is the one telling them this, everyone believes them.
The plot is revealed to have been orchestrated by the Belkans as revenge for the sound thrashing they took fifteen years ago. If what we see of the Osean government in this game is any indication, this means that in just fifteen years the entirety of both the Osean and Yuktobanian governments, excluding the former's President and the latter's Prime Minister, have become composed solely of traitors who want nothing but to ruin their own country.
The ending of Fallout 3 potentially has a whole group of people making a really dumb decision. The Lone Wanderer is forced to either make a Heroic Sacrifice or make another human character do it (depending on the player's chosen place on the Karma Meter). Either way, someone has to get doused with a lethal amount of radiation. However, two of the possible companions in the game are a super mutant and a ghoul, both of whom are immune to radiation. The characters could send one of them in (if either one is present) with no loss of life. However, if you have the Broken Steel DLC installed before finishing the game (a DLC that has quests that take place after the main game is over), the Idiot Ball and the plot-ending sacrifice can be averted by sending in an immune companion, though the game still regards this as a coward's way out.
In 7 Days A Skeptic, almost everyone on the ship carry their own Idiot Ball, and the engineers who built the ship brought theirs to work. The whole plot relies for one part on everybody being inefficient at their jobs (the engineer refuses to repair anything, while the security chief sends you to track down a missing person, then arrests you when you find the body) and for another part on the ship being an incompetently constructed deathtrap. (Escape pods that take hours to prep? A cabin with a lock override that can only be accessed from the inside? Radio antennas capable of skewering an unwary bystander? Also, no railings around the edge of the engine pit, and a fancy glass-domed observation deck with no signs of protective bracing or ways to seal it off if it breaks.) And of course, when the ship is haunted by a killer and you have to wait a few hours to get the pods ready, you should definitely split up and take a nap.
When he realized that Kerrigan was controlling Raszagal and using the Protoss for her own ends, Aldaris started a civil war instead of voicing his concerns to Zeratul, who already suspected something was wrong with Raszagal.
After the UED find and take control of the Psi Disrupter, which would cripple the Zerg, Duran convinces Du Galle to destroy it, in case the already-crippled Dominion, which had written the Disrupter off as an urban legend, might find it. Leaving behind a garrison doesn't even come up.
When Stukov realizes Duran's a traitor and probably infested after Raynor and Mengsk escape, he takes his own men to operate the Psi Disrupter, which he'd left standing despite orders to destroy it. He doesn't explain to Du Galle where he went or why the mission failed. Meanwhile, Du Galle is having his own moment of contrived stupidity, taking Duran's advice to order Stukov, his childhood friend, arrested or executed, without asking what happened in the previous mission or realizing that the Disrupter might be useful. Throughout the briefing, the Player Character, who sawDuran commit treason and let the previous mission fail, doesn't say a word.
Once they do have the Disruptor up and running, the UED leave only a couple of Siege Tanks and a half-dozen Marines to protect its sole power source. No backup generators, no attempts to duplicate the Disruptor, and when the Player Character comes to destroy it in the Zerg campaign, the UED doesn't immediately scramble all their troops to defend it. On the other hand, it does explain why they never previously thought of leaving a garrison to protect the Disruptor, since they obviously don't get the concept.
Raynor, Mengsk, Fenix, and Zeratul all gladly ally with Kerrigan after she manipulated them into doing her dirty work and established herself as a borderline sociopath in the process. This is especially galling for Fenix and Zeratul, since Kerrigan played them like chumps in the Protoss campaign.
Remember Me suffers from this in a pretty bad way. Nilin is a Memory Hunter with a special talent for "remixing" memories, the ability to edit a person's perception of a past event to alter their perceptions and behaviors. She knows this. So after she's brainwashed, she doesn't question anything anyone tells her and just blindly follows orders, even after it's become very, very obvious that Edge, her mission coordinator, is a terrorist.
Dante's Inferno has Beatrice betting the devil that her paramour Dante will remain faithful to her while he's off fighting in the Crusades, wagering her soul to Satan in exchange for...nothing in particular. Guess what happens next?
Not to mention that Dante is only in the Crusades because the Obviously Evil bishop convinced him to enlist. He even completes his moment of idiocy by adding, "Would a bishop lie?"
Metroid: Other M is ostensibly about a team of elite soldiers led by the "greatest military mind", but the soldiers wander around like the Space Trucker crew from Alien and Adam has some form of short-term memory loss given how often he forgets to direct his troops properly or pay attention to the backstabbing assassin that's infiltrated his unit.
Yoshi's New Island would have us believe that the entire reason we're hauling Baby Mario across all of creation for a third time is because the Stork delivered the babies to the wrong house. Somehow. Despite, you know, having a map.
Played for Laughs in Octodad. The entire premise is about people being too dumb to realize that the protagonist is not a human, but an octopus. Granted, they can get suspicious about it, but the flopping about and lack of fingers tips them off only so much that they can become 99.99 percent sure that he's an octopus, but not act on it until they're 100 percent sure.