"The materials used to create a lock are of utmost importance. Shoddy brass or copper will give way to a well placed kick, thereby rendering the lock itself useless. I recommend steel over iron when choosing a material. More robust materials tend to be prohibitively expensive and necessitate the door being made of similar metals. I have been chagrined to stumble across the shattered shell of a wooden chest, its dwarven lock intact and still locked."This door is absolutely impenetrable. It's made of 100% Indestructium, is guarded by robot monkeys with crossbows, and opens only to authorized personnel who pass the DNA test, pass the retina scan and present a valid birth certificate. Yes, no one will ever force his way into — did you just break the door off its hinges? This is Crippling Overspecialization applied to architecture. A designer puts immense effort and resources into a structure, most often a defensive point such as a wall, door, or window, but fails to notice a large weakness in the design that makes all of this easy to circumvent. The most common flaw being that for all that the door itself is indestructible, the wall around it is less so. This is especially so in Chinese and Japanese media where many walls are made out of paper. Often, the floor will also be vulnerable to burrowing. The door itself may not be that hard to open, especially if We Have the Keys. Often played for laughs if the way through the apparently impenetrable defense is particularly obvious or easy. Sometimes serves as a Reality Ensues moment. A common justification in-universe, and most Real Life examples as well, are cases of Didn't Think This Through. Compare Dungeon Bypass, Cutting the Knot, Override Command, Steal the Surroundings, Absurdly Ineffective Barricade, Inventional Wisdom. Contrast There Was a Door.
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- Played straight in a TV ad for a French reinforced door company: France's equivalent of a SWAT team is raiding an apartment building and hits a particular door with a battering ram: This takes several tries, and only makes a huge hole in the wall around it, with the door and its frame still standing.
Cop: This is the second time this week...
Anime & Manga
- In one chapter of Sgt. Frog, the Keronians test out their new security system on Momoka's mother Ouka, who wants to get her hands on Keroro for some reason. The first obstacle is a series of electronic locks on the mini-fridge that serves as the main entrance to the lair. What does Ouka do? Rip the door off its hinges.
- In the finale arc in the manga Ranma ½, Akane is held in a cell by the bird tribe. She desperately tries to kick and ram the bars through to no avail. In her frustration, she leans to one side... and tears open the flimsy lock on the cell.
- In an early episode of Ghost in the Shell: Stand Alone Complex, a cautious Togusa decides to open a door carefully in such a manner that he wouldn't set off any potential traps that may be rigged up. An impatient Batou says that it's an admirable skill to have, but they are in a hurry to bust a criminal. He kicks the door in, busting the bolt off the door in the process.
- Happens twice in Hunter × Hunter:
- During the Hunter Exam, the group of main characters are given a Sadistic Choice in the form of a fork in the road: A path that takes many hours to walk through that all five can enter and a path that takes only 5 minutes that only one person can enter. The team only has several minutes left before time runs out and they are disqualified, so the solution they decide upon is to go through the long path meant for five people, then punch through the wall separating the two paths and climb through the hole to take the short path.
- When Gon and Killua get captured by the Phantom Troupe, Nobunaga wants to nominate Gon into the troupe and chooses to keep them captive in an abandoned apartment building room until the troupe's leader returns. To that end, Nobunaga chooses a room with only one door and guards it, always keeping watch. Gon and Killua escape by each punching a hole through walls on opposite sides of the room, shocking Nobunaga and paralyzing him with indecision so the boys could create some distance from him, and they continue to punch holes through walls around the building to confuse Nobunaga long enough to leave the building and entirely out of Nobunaga's reach.
- Doctor Strange:
- Strange's own Sanctum Sanctorum is guarded by warding spells linked to its characteristic round window. A band of his enemies once gained access by breaking down the wood of the windowframe, causing the whole thing to fall apart.
- In Doctor Strange: The Oath, a door is sealed with a magic sigil. Strange asks Wong to break the door down. Seconds later, the Night Nurse calmly picks the lock with a hairpin.
- Disney Ducks Comic Universe: Scrooge McDuck has sometimes found himself in trouble because his impenetrable Money Bin with unbreakable walls and gates lacked a proper floor and/or foundations due to the owner's stinginess.
- A running gag in the Lucky Luke album "The Daily Star" resolves around a sherrif who takes great pride in the fact that the bars of the cell in his office are unbreakable, which he claims will prevent any escape attempts. Although he is right about the strength of the bars, the rest of the office is not that strong so it’s still very much a Card Board Prison. At the end of the story, the entire sheriff office is destroyed with only the bars still standing.
- Hägar the Horrible:
- There is a strip where Hagar returns from a plundering, handing Helga a large, well-crafted castle-style lock, noting that she's been worried about people breaking into their house. She's initially overjoyed, until she asks where he got it. "Oh, it wasn't too hard — it only took me five seconds to rip it out."
- In another strip, the occupants of a castle brag about how strong their door is. Hagar hits it with a battering ram and the door is unharmed. The rest of the castle fell down around it.
- In a Gnasher and Gnipper strip, after the dogs knock over Dad one time too many, he buys a pair of special gnash-proof chains to keep them restrained. Fortunately for the dogs, while the chains were completely gnash-proof, the wall wasn't.
- In the Project Dark Jade fic Shadows Awakening, the gates to the Forge of Shadows are indestructible, but the walls aren't, allowing the heroes to blast their way in. Kyosuke/The Phantom admits this was an oversight, but defends himself by saying that it was built before his time.
- In the other Project Dark Jade fic Webwork, Uncle has made the Vault door impervious to attack by evil magic. However, he wasn't able to do this for the surrounding walls, so Jade has her Shadowkhan chip away at those to weaken the door enough for her to pull it loose. Uncle calls this cheating.
- In Storybook Hero, after Harry Potter and some of his friends are arrested, he and a half-giant break out of a cell with an indestructible door by punching it until the hinges broke.
- In one of a collection of one-shots, a Kryptonian Harry Potter punches a locked door and finds it is indestructible (and punching it hurt his fist). However, the impact cracked the archway around the door and the door fell down a moment later, much to Harry's annoyance.
- In the Touhou fanfiction FREAKIN GENSOKYO, barriers and locked doors sometimes block the way deeper into a building. The walls around the door, however are usually not as strong. Brad takes advantage of this by breaking through them wuth an enchanted plant hanger.
Films — Live-Action
- Pirates of the Caribbean: The Curse of the Black Pearl presents a lesson: Don't build a jail door using half-pin barrel hinges. Although it's implied that Will only knows how to break the door because he helped build it.
- Pirates Of The Carribean At Worlds End has a return of the half-barrel hinge on a jail door, enabling Jack to extricate himself again after one of his hallucinated doppelgangers notices it, and he remembers "leverage".
- Star Wars has the Death Star, a planet-destroying space station. It can only be destroyed by firing missiles down a small exhaust port which directly leads to the main reactor; said port is at the end of a trench that cannot be easily defended by fighters or defence turrets. However, given the fact that the exhaust port was so small that only a Force-user could make the shot - and there were about two Force-users in the galaxy not working for the Empire at this point - it's not as Myopic as often thought.
- Justified with Helms Deep in The Lord of the Rings, as the designers could not have anticipated that Saruman would use explosives, mostly because he apparently invented them just for this battle.
- In The Pink Panther (1963), Inspector Clouseau is prepared to shoot the lock when Mr. Tucker says, "Don't do that old man" and opens the door.
- In RED, Frank Moses circumvents a password-protected lock that he describes as "unbreakable" by kicking a hole in the flimsy drywall next to it and opening the door from the inside.
- In Sneakers, Bishop is confronted with an electronic door lock that was installed soon before his break-in. He radios for help; the team is not happy; and after a few moments of silence while (only) he hears the plan, he simply kicks the door open.
- In the 2004 Coen Brother's version of The Ladykillers, this comes into play with the design of the underground casino vault in which the characters are stealing from. The door and walls bordering other rooms in the building are highly secure and reinforced, however the wall facing outwards (to underground soil) is just a normal wall. The characters exploit this weakness by tunneling under ground from a nearby cellar to the casino vault, and right through the wall. After emptying the vault they close up the hole in the wall to make it look like it was never penetrated, and they use explosive to destroy the tunnel behind them.
- In Toys, The Tommy Tanks try to break into the warehouse where Leslie and company are hiding. After a few bashes on the door, they decide to blow up the wall next to it.
- A kangaroo is brought to a zoo for a new exhibit. The next day, the kangaroo is found hopping around outside his exhibit. The zookeepers return the kangaroo to his cage and raise the fence. The kangaroo escapes again, the zookeepers recapture the kangaroo, and they raise the fence again. This continues until the fence is a ridiculous height, yet the kangaroo keeps escaping. Finally, a patron figures out the problem: none of the zookeepers had remembered to lock the gate.
- The main gate of Redwall Abbey is large and thick, impervious to even the most dedicated of sieges. Basically, not one invading vermin horde has ever gotten through it. The tiny wicker side-gate, on the other hand, has been breached by countless invading hordes over the seasons (or the youngest of the Abbey's children are forever escaping into the woods and into the villain's clutches), probably accounting for every successful invasion of the abbey. This is presumably intentional, since it would be easy to station three well-armed, armoured guards there during a siege to hack up any single file intruders who tried to get in. Unfortunately, being peaceful monk and villagers (nearly every book is set so far apart in time almost no one remembers times of war), the Redwall inhabitants never think of that.
- In The Bellmaker, the heroes are able to escape their prison cell by hacking the hinges (which are on the inside) off. Which is justified, as the heroes' "prison" was a peaceful residence, and was invaded only weeks back. The occupiers locked the heroes into the tallest tower, i.e. the place with the least chance of escape (but it is heavily suggested -because of it being the tallest tower-, that it probably was the keep, and hence built defensively. Therefore, the hinges naturally were on the inside).
- In Guards! Guards!, Vetinari is revealed to have done this on purpose: while the lock to the palace dungeon is on the outside, the locking mechanisms are on the inside. Would-be usurpers throw him in the dungeon expecting it to serve as a Tailor-Made Prison; instead, it's an impregnable fortress that he can "escape" at his leisure.
- In The Last Continent, Rincewind discovers that the cell doors in the XXXX jail have thick bars, sturdy locks... and weak half-pin hinges.note
- At one point a point is made of the wonderfully-made reinforced hinges on the door of the notorious bar The Mended Drum. The point made is that they held up beautifully as the whole frame was ripped from the wall.
- In Interesting Times, Cohen and the Silver Horde are more or less free to roam about the castle, due to being the only ones who think to walk through the paper walls.
Six Beneficent Winds: But you can't go through walls!
Cohen: Why not?
Six Beneficent Winds: They're — well, they're walls. What would happen if everyone walked through walls? What do you think doors are for?
Cohen: I think they're for other people.
- Used in Jingo by Nobby, as a joke on a common nostalgic phrase: "We never had locks on our doors in those days... that's 'cause the bastards even used to steal the locks".
- In Wyrd Sisters Nanny Ogg is a guest in Duke Felmet's torture chamber, on the wrong side of a semingly impregnable oak door with five-inch planks and a very big lock. Junior witch Magrat Garlick is faced with the problem of opening it. Magrat focuses. And gets in tune with the wood of the planks, reminding the old seasoned oak of happier days growing in the forest. There is a sudden eruption of oak tree in full green bloom, and suddenly there is no door. This gets Magrat a rare word of praise from Granny Weatherwax, who has also been contemplating the same problem.note
- In Anansi Boys a police specialist bemoans Graham Coates' security arrangements, pointing out that he installed a wonderfully secure door, then hung a lock on it that the specialist picked effortlessly.
- In Artemis Fowl when Butler is rescuing Artemis (trapped in his "secure" office because the lock had been welded shut), he blasts the frame instead of firing at the door itself. He notes that the security flaw should be fixed even as he exploits it.
Butler put three rounds into the door frame. The door itself was steel and would have sent the Devastator slugs ricocheting straight back at him. But the frame was the original porous stone used to build the manor. It crumbled like chalk. A very basic security flaw, and one that would have to be remedied once this business was over.
- In one of Christopher Anvil's Interstellar Patrol stories, the villain boasts of how impregnable his Elaborate Underground Base is. When the protagonist puts this to the test, he finds that neither the villain nor his contractors realised that it's no good having foot-thick walls if they only go up to ceiling height, with a convenient access void above them.
- In The Revenge of the Demon Headmaster, this occurs near the end of the book:
"That won't get you out. The door is solid metal, one metre thick."
"But I bet the walls aren't."
- Discussed and averted in the satirical poem "The Deacon's Masterpiece, or, The Wonderful One-Hoss Shay", in which the eponymous vehicle is made "so like in every part" that there is no weak point that could cause it to break down. After a century of use, the whole thing disintegrates at once.
- Said poem is sometimes referenced in engineering classes as it's connected to a real-life design dilemma: actually design a specific weak point whose lifespan is measurable and which can be easily replaced (the electric fuse being an excellent example), try to guess at and reinforce the points of major wear (which you often get wrong), or try to build everything equally strong at the cost of having no idea how long the thing will last or what kind of repairs it might end up needing.
- This trope turns up in the Phryne Fisher book Death Before Wicket in relation to a safe that was cracked. It's a very big, impressive, well-built safe... except that the back isn't, because the safe was made to be set in a wall. The present owners purchased it from a deceased estate and didn't know about the intended setting, so they simply left it on a desk, where the thief easily found it and removed the back.
- In Forests of the Night, the previous tenant of Nohar's apartment was a paranoid who replaced the front door with a heavy bulletproof door. Nohar speculates on how useful this would be considering the wall around it is normal wood and plaster. He later uses this door, unhinged, as a shield during a firefight.
- In one episode of The Mentalist, the Victim of the Week was killed via exposure to a deadly virus kept in a high security vault accessed by retina scan - which didn't work right and would let in anybody who presented their eye for scanning.
- A minor example in Terminator: The Sarah Connor Chronicles, someone shuts a metal security door in their faces, and Sarah asks Cameron if she can get through it. Being a Terminator she could given time, but it's faster to punch a hole in the concrete wall. Of course, the person they were going after was expecting human pursuers, against whom the wall would have been sufficient.
- A common conceit in Michael Weston's voice-overs on Burn Notice is that people are more apt to reinforce doors than the nearby walls.
- In an episode of MacGyver, he's at a college supervising a day in which students who have locked the doors of their dorm rooms in various creative ways change places and try to open them. One student's room isn't locked at all. This plot was based on an actual annual event at Caltech.
- In the Doctor Who serial "The Space Museum", companion Vicki is helping the natives to break into a weapons storage facility so they can overthrow the aliens who took over their planet. The computer guarding the door can tell if people are lying to it, which thieves logically would, so it doesn't check to make sure that truthful answers are good answers, allowing her to break in with following exchange:
Computer: Do you have the Governer's permission to approach?
Computer: State your name, rank, and number.
Vicki: Vicki, time-traveler, no number.
Computer: Do you have proper authorisation for the removal of arms?
Computer! From whom do you have this authority?
Vicki: From Tor, Sita, Gyar, and Bo. Oh, and Dako. Let's not forget Dako.note
Computer: What is their rank?
Vicki: Xeron workers.
Computer: For what purpose are the arms required?
- MythBusters: In the myth "Salsa Escape", Adam and Jamie were testing the use of salsa to dissolve the iron bars of a prison cell. Adam's attempt to use electrolysis to accelerate the process failed because he used alternating current rather than direct current (indeed, it ended up making the bars thicker). Jamie's attempt with direct current worked far better. After several failed attempts by Adam to break his bars using alternate methods, Adam had "one last attempt" which succeeded—using the nearby sink to punch a hole through the (unreinforced) cinder block wall.
Adam: And I escaped! In your face, iron bar!
- In The Monkey King televised miniseries Nicholas Orton (Thomas Gibson) a Fish out of Temporal Water teaches Confucius a lesson of his he learned, never make a indestructible door without a indestructible wall around it.
- Happens more often than you think in Tabletop Role Playing Games; savvy players always check hinges, floors and walls when attempting a Dungeon Bypass, and inexperienced GMs don't always plan for this (though some crafty GMs may actually invoke this, especially when dealing with a group of savvy players). The oldest standby is the fighter as the back up lockpicker. If the thief can't make his lock picking check, the fighter can always bash down the door. Of course, a well-designed dungeon will make sure the noise alerts monsters and sets up ambushes.
- In A Very Potter Musical, Ron assures everyone that Voldemort can't get in, because he's barricaded the door. Seconds later, Voldemort enters through a curtain right next to the door.
- In the opening of Freedom Planet, Big Bad Lord Brevon enters the royal palace by burrowing beneath it, to the shock of the royals who thought that the walls of their castle were impenetrable. As Brevon himself notes, the walls are impenetrable; the floor, however, is not.
- Knights of the Old Republic
- Often exploited by Revan. If you don't have a high enough skill to hack through the door lock, there's usually the option of just destroying the door or a section of the wall next to it.
- Jolee points out a particularly terrible case of it on Kashyyyk, the Wookie homeworld. Czerka Corporation wants to keep everyone away from its MacGuffin site ( the Star Map), and does so by plonking a giant force field down across the only available path on the surface. Unfortunately for them, Wookies are arboreal and can simply climb around it.
- The Big Bad of Second Sight eventually hides himself in a room behind a large pane of glass which, apparently, is immune to not only bullets but all of your various psychic powers. Too bad for him the frame is ordinary metal.
- The Secret of Monkey Island:
- In the first game, if you let Guybrush be recaptured by the cannibals, they'll progressively beef up the security of their prison hut, eventually installing an all-steel door with a motion detector, never thinking that there might be a large hole in the hut floor.
- The second game has one as well. After a maze Guybrush is confronted with a MASSIVE door with hundreds of locks, Schizo Tech styled security, and chains all over. He opens it by using the open command on it. And what opens is just a small rectangle within the whole structure, suggesting that all those metaphorical bells and whistles are only there for show.
- Similarly, in Leisure Suit Larry 7, the door to the staff room is heavy steel and, if you get too close, about a hundred weapons emerge from the walls to point directly at your head. Security measures include testers for DNA, fingerprints, retinal scans, tongue prints, and urine analysis. But, it turns out, the latch doesn't work properly and you can get in by just pushing on it. To be fair, the option isn't among the list of available commands on the door. You have to type it in.
- Similarly to the Pirates example above is the cell door on the pirate island in Shadow Hearts: To the New World. Natan just lifts it up and walks out.
- The Elder Scrolls IV: Oblivion discusses this, as quoted above.
- A common mistake for newbies to Dwarf Fortress, rarely realized until the fort's defenses are put to the test.
- Commonly seen in Minecraft. Someone will go through a ridiculous procedure to create an incredibly elaborate safe that takes a full 5 minutes to open and someone else will simply dig through the wall. Also, many adventure maps start with the player locked in a cell, with one wall made out of a block that the rules of the map say they're allowed to break (usually clay), allowing them to easily escape into the hallway or an unlocked neighboring cell.
- Jagged Alliance 2 has several locations with doors that are extremely difficult to lockpick and resilient enough to withstand a blast from an anti-tank rocket. The walls these doors are placed in, however, are completely ordinary and can be blasted to rubble with an ordinary dynamite stick.
- The Geomod engine from the first Red Faction game let the player destroy just about anything in the environment. Bulletproof windows, however, were completely indestructible. The walls around them were not. With enough explosives, a player could leave a glass pane floating in the middle of a twelve food wide void.
- In The Legend of Zelda: Majora's Mask, the gate to the castle of Ikana is sealed and cannot be opened by any means... too bad there's a big hole in the wall right next to it.
- Amusingly, the presence of the hole seems to indicate that this trope occurred to Ikana's enemies in Termina's history.
- Modern Warfare 3's penultimate mission has your team encountering a room in an underground mine protected by a reinforced titanium door that you have no way of opening. So how do you get in? By planting shaped charges... on the much weaker concrete roof of the room.
- Ghostbusters: The Video Game has "a psychonically-charged gate attached to a damaged frame" as the second-to-last obstacle in the graveyard level. Of course, the stone cherubs are the only way to get it open...
- Played for Laughs earlier in the "Return to Sedgewick Hotel" level's cutscene. There's a lot of police-tape over the main door, as well as a sign from Walter Peck's agency, PCOC, that forbids anyone from entering—"ESPECIALLY THE GHOSTBUSTERS!" Ray suggests blasting through the doors, but Egon calmly opens the unlocked door.
- Braum's shield in League of Legends used to be a door to a magic vault. The door was unbreakable. The mountain the vault was part of wasn't.
- Hatoful Boyfriend Holiday Star: Sakuya insists that a room's security is flawless and so he can display an item legendary thieves are seeking without fear. None of the other characters are convinced or surprised when, indeed, the room is broken into, and they react with exasperation finding that the security was impeccable... around the door. Despite a window, and most characters in the game being capable of flight.
"What kind of rascal blows their way in through the wall!? If they’re going to break in, why not act with some semblance of decency and come in through the door!?"
- At one point in Ruby Quest, Ruby and Tom come across a door locked with a keycard reader. However, the door is made of wood, so the players just have Tom smash it to pieces with his crowbar.
- Homestuck. HB: Pry the wall from the safe. (Unfortunately, "That notion is even more ridiculous than the last one.")
- Sluggy Freelance uses this trope twice in the Sluggy of the Living Freelance storyline.
- One of the Tempts Fate fundraiser comics from Goblins had the protagonist come to a magical talking door that asked anyone who approached an incredibly difficult riddle. If they answered incorrectly, it would trigger an instant-death trap. The door never said it was locked. Tempts simply opened the door and walked through without giving an answer at all.
- In Art Of Domination, it's revealed one building's owner didn't have anywhere near enough funds to make it an impregnable fortress... so instead they focused on a big, attention-grabbing, indestructible door in hopes that it would make hostiles overlook the walls. It worked.
- In Freefall, the Mayor's house has a top-notch security system, with one crucial oversight:
Sam: (Picking up chainsaw) Of course, after this, she's going to start fortifying the walls.
- Elf Blood: To be fair, the architects for the temple defenses designed their extra-fortified mastercraft-warded doors around solid bedrock. Problem is, none of the architects knew about dynamite.
- The Simpsons
- One scene in the nuke plant in "Last Exit to Springfield" involved Burns and Smithers going through several layers of increasing security to reach a control room, which was seen to also feature an ill-fitting, flapping screen door leading directly to the parking lot, through which Burns has to shoo away a stray dog.
- The episode "Realty Bites" has a seized property police auction, where the cops are selling a large iron gate that was designed to resist bullets, explosives and battering rams. When asked how they managed to get though it, Chief Wiggum says the owner left it unlocked.
- There's also the episode in Japan, where Homer is arrested. The cell door looks imposing. But after being released, Homer just walks through the paper wall next to it.
- In an episode of The Fantastic Four (1967), Diablo is running from Thing and retreats into a panic room. He assumes he's safe, since the door is made of titanium, which Thing is not strong enough to break. When Thing reaches to room, he just breaks through the wall.
- Example of Myopic Clothing in the Looney Tunes short Duck Dodgers in the 24½th Century. Dodgers wears a disintegration-proof vest. Sure enough, the vest itself survives the disintegration, but not the duck inside it.
- One episode of Chowder has Mung putting Chowder in a cage, but the bars are so weak that he's able to easily break them apart. He tunnels his way out.
- In the Phineas and Ferb episode "A Hard Day's Knight", when Perry is fighting Dr. Doofenshmirtz in a robot of Queen Elizabeth I the latter is piloting a robot dragon and tries to make it breathe fire, only to find that the flamethrower and the pilot's seat are both located in the mouth but the flamethrower is behind the pilot. He then lampshades this.
- Keep in mind that Doof didn't even build the dragon; he and Perry were at a mad scientist convention and they took the robots from the showroom, so him being dissatisfied with the cockpit/flamethrower placement was completely justified.
- In the American Dad! episode "Toy Whorey", Roger's cliffside estate has the garage doors leading over the cliff, so when he backs up out of the garage he falls over.
- In the Steven Universe episode "Onion Friend", Steven tries to keep Onion from stealing a bag of chips by blocking the door to his room. So, Onion just jumps out the screen window instead.
Steven: ONION! We just put that screen in!
- After a long and bloody siege that they had pretty well held off up to that point, Constantinople finally fell when someone left a small supply gate open, allowing the invading army to come in.
- The World War II Maginot Line is an example in the popular imagination which was actually a subversion; it was a wise investment of resources which did exactly what it was supposed to. That is, its existence caused the first operation of the war in the West to be fought in Belgium while minimising the forces needed to hold the Franco-German border. Unfortunately, the French Army had three largely unavoidable issues which had nothing to do with Maginot.
- The French conception of warfare was so exclusively focused on Tactical supremacy that it had completely forsaken Operational-Level mobility.
- The French conception of warfare was limited in scope, having no Operational Level. French performance at the Operational Level was therefore dependent on their commanders' own ideas about warfare. The French Operational Commander, Foch, was typical of the French Army in that he barely understood it.
- Foch's Operational Plan stank. He foresook the French Army's strengths (taking and holding well-prepared lines) and tried to use it for something it was never designed for - an Operation of rapid movement. There was a good strategic rationale for this, given the logic behind preserving Dutch and Belgian industry, but it was still a risky move for an Army not designed or suited to execute it to attempt it against an Army that very much was. note
- Cryptography brings us the "Single Point of Failure". Basically, if each part of your system is secured with a different password, a cracker who gets just one of those passwords will have a hard time doing much damage. But if you use the same password for everything, you're hosed.
- Cryptography has this issue in more ways than one. There are branches of mathematics devoted to developing crypto-systems that are pretty much mathematically guaranteed to be secure. However, once these systems are developed, they are turned over to people who use passwords like "password" or leave their login information on a little sticky note on the monitor.
- Computer Security is pretty much governed by this trope. Unlike other security systems, an attacker doesn't get hurt if they fail to break in. So they simply try every conceivable way into a system.
- Thus leading to the following expression: "The user is the biggest threat to any security system."
- And the euphemism "lead-pipe cryptanalysis" (or "rubber-hose cryptanalysis", based on the idea that the weakest part of any security system is the squishy one that types the passwords.)
- Cryptography has this issue in more ways than one. There are branches of mathematics devoted to developing crypto-systems that are pretty much mathematically guaranteed to be secure. However, once these systems are developed, they are turned over to people who use passwords like "password" or leave their login information on a little sticky note on the monitor.
- Because of this trope is that the Jules Rimet Trophy (the first trophy used during the world cups) was stolen so easily. When the Brazilian team won the cup for the third time in 1970, they were allowed to keep the real trophy in perpetuity, since Jules Rimet stipulated that in 1930. It was put on display at the Brazilian Football Confederation in Rio de Janeiro encased in bulletproof glass so it wouldn't be stolen. The problem was that the rear of the cabinet was made of simple wood, so in 1983 it was easily opened with a crowbar and stolen. Sadly, it was never recovered.
- Truth in television: Some of the better deadbolts can withstand forces that would put a hole in an outer wall. And, of course, there are a lot of houses that have solid steel doors with deadbolts and security screen doors... and great big picture windows right next to them.
- Straitjackets are designed this way, in that someone who's both mentally-rational and moderately flexible can often work their way out of them after a few tries.
- A variation of this trope is occasionally invoked for hostage rescue; if the suspects have at least one firearm trained on each door or window, the safest way of gaining entry is to take a shaped charge to a wall and attack from an unexpected direction. Naturally, this solution is not employed unless the police or Special Forces team can obtain the building plans, lest they blow a hole in a load-bearing wall.
- During the Second World War Battle of Ortona, German forces were heavily entrenched in the houses of the town. Entering through the doors or windows was too dangerous, so the attacking Canadians simply blasted holes in the walls with their rocket launchers and anti-tank guns.
- Speaking of World War II, seismic bombs such as the Tallboy and the Grand Slam were developed to exploit this sort of thinking. Rather than try to break through a bunker's heavily-armed ceiling — which might be breached but would likely absorb most of the blast, protecting the occupants — these bombs were instead designed to penetrate deep beneath the ground next to the target and explode, undermining the foundations and causing the whole structure to collapse in on itself.
- German battleships Bismarck and Tirpitz had been built with tremendously durable hulls and armor, able to survive and move under their own power after a direct hit from the said Tallboy bomb. The direct hit had been a necessity, since their armored decks were mostly impervious to standard Royal Navy 500lbs and 1600lbs bombs. Their stern construction, however, made impossible the steering via propellers only and left most of the rudders and steering engines poorly protected. The Kriegsmarine knew that after Bismarck sea trials, but did not expect it to hamper the ship's fighting ability. Unfortunately it did, as a single lucky shot from a torpedo broke the rudders and left Bismarck a sitting duck in her first raid.
- On the topic of warships, warship armor protection evolved due to this trope. Originally, it was common for ships to have the thickest armor around the sides, bow, and stern, to protect from direct enemy gunfire. Improvements in artillery and rangefinding lead to the addition of armor protection against "plunging fire", as the longest ranged artillery would be fired on a ballistic trajectory. The introduction of sea mines and torpedoes necessitated armor protection under the waterline as well, and improvements in weapons technology lead to "All-or-Nothing" armor protection, where all of the ship's most vital bits were packed together and encased in a heavy armored citadel, while the rest of the ship (galleys, living spaces, cargo holds, etc.), necessary to her operation but not to her surviving combat, was left almost entirely unprotected to leave the ship light enough to avoid speed and range penalties. Eventually, ship designers gave up on armor protection for the most part and now build lightly armored warships that are armed with massive batteries of anti-ship and anti-air misisles instead.
- Portable safes. If a thief gets into your house without raising an alarm, there's not much stopping him from just walking off with the whole thing. Many of these safes are designed to be bolted to the floor, but otherwise you've just made things into one-stop shopping for the thief.