In David Eddings' The Belgariad, the character Lelldorin manages to extend an epic fail over the course of several weeks. When he announces that he's going to get back to the main group, his beloved refuses to stay behind. During the departure and trip, he manages to break her father's leg, run his cousin through the leg "just a little bit", punch out all of a priest's teeth, and cause enough assorted mayhem to get a bounty put on his head by the crown. And all of this was without trying. This is also an example of Disaster Dominoes.
He did successfully marry the girl in the process, though! He claims traveling alone with an unwed woman would have caused more trouble, but considering getting married involved punching out said priest's teeth...
In The Mallorean, Garion has to stop a war threatening to engulf the entire kingdom of Arendia. He magically summons a storm that helps him single-handedly stop two charging armies in their tracks, force an old friend to marry the love of his life, and resolve the dispute. Hes very pleased with his hard days work. A few chapters later, he finds out that he sparked off blizzards, hurricanes, droughts, and tornados right around the world, and even triggered a new ice age. It took the combined efforts of the Gods themselves and two of the most powerful sorcerers alive over six months to fix it. Needless to say, Garion is banned from touching the weather again for two thousand years.
In Isaac Asimov's The Caves of Steel, Elijah Baley is investigating a murder and has a robot partner that appears physically identical to the murder victim. He goes to the people who reported the murder, announces his theory that the robot is, in fact, the murder victim, and gives an extended justification. The entire "murder" was a scheme, it was the robot that had been destroyed to produce the "body," and here are the point-by-point reasons why all the supposedly "robotic" actions of his partner actually match perfectly with a human impersonating a robot. All the while, his boss is watching via a teleconference. After the completion of the detailed and rational accusation, said alleged non-robot opens up his sleeve and then calmly opens his arm as well. Elijah faintsnote Although at the end, Elijah hints that this is Obfuscating Stupidity.
Codex Alera: The First Aleran Legion, before they have collectively Taken A Level In Badass, are prone to this. The single Knight Ignus is being treated for burn wounds, and while the Knights Aeris can fly up, they aren't very good at getting down again. They wind up getting the nickname "Knights Pisces," since they act more like landed fish than legionnaires.
A anything created by "Bloody Stupid" Johnson is likely to fall into this to such a degree it crosses over into Achievements in Ignorance. Anyone can create a garden fountain that doesn't work. It took Johnson to create one that creaked for half an hour and then shot a stone cherub a hundred feet into the air. Or crazy paving that committed suicide. A badly designed apartment block is easy. But only Johnson could draw plans so bad the resulting building warps space-time. Despite this his inventions usually work quite well, only at something entirely unrelated to their intended purpose such as the manicure device which makes a very handy automatic potato peeler.
A related level of "talent" can be found in Cut-Me-Own-Throat Dibbler and his various international counterparts. The original's sausages inna bun have been compared to a B-movie—horrible but strangely compelling—but when he tried to branch out into cultural cuisine he got similar complaints from the other species of Ankh-Morpork, such as trying to sell stale rocks to the trolls.
The Counting Pines in "Reaper Man" believed that the reason humanity cuts down trees is because they want to see how old these trees are by looking at annual rings. Thus, they evolved to show their age on their bark, and within a year were nearly driven to extinction by the ornamental house number plate industry.
Perhaps the funniest part of The Divine Comedy is the revelation that Adam and Eve were in Eden for about six or seven hours before they were kicked out for breaking God's very simple rules.
In A Feast For Crows, the book ends with a very dramatic reveal of a plot to marry Quentyn Martell, a prince of Dorne, to Danaerys Targaryen, overthrow the government, and put her on the throne. Late in A Dance with Dragons, a mysterious stranger arrives in Danaerys' camp, reveals himself to be Quentyn, and promises her love and a throne. She turns him down, although she hints that they can make an alliance or political marriage later. He is so desperate to return home with something to show for his gambit that he tries to abduct two of her dragons. They promptly burn him so horrifically that he dies blind and in agony several days later. Nobody Shoots the Shaggy Dog like GRRM.
Fiasco by Stanisław Lem. Full stop. It starts with young pilot named Parvis going on a rescue mission to save his mentor and fellow Chronic Hero Syndrome sufferer Pirx - this mission goes wrong and Parvis has to use an emergency procedure to become a Human Popsicle till he gets rescued himself. Two and a half centuries later. When they practically have to rebuild him, and he still gets retrograde amnesia so severe that he's not sure whether he's really Parvis - or Pirx (his rescuers don't know because of a bureaucratic screw-up). But that's only the beginning! The ship that's rescued him is on a mission to contact an alien civilisation which proves unable, unwilling, or both, to have any meaningful relationship with humanity. The First Contact attempts repeatedly fail, in progessively destructive ways, culminating in the entire planet, with probably-Parvis on it, getting destroyed because he got so engrossed he hadn't reported on time.
Crabbe, along with Malfoy and Goyle, corner Harry and his friends in the Room of Requirement. During the battle, he casts Fiend Fyre, an uncontrollable, unquenchable fire that consumes everything in the room... including him and the very magical artifact that Harry had gone in there to destroy. Nice Job Fixing It, Villain!.
Voldemort kills himself with his own Killing Curse that rebounded back at him. It wasn't the first time it happened. On top of that, Harry told him what was going to happen.
In Horus Heresy, often the greatest obstacle in the villain's path is the villain himself:
In Fear To Tread, Ka'bandha's plan is to confront the Blood Angels with his armies and amp up the Angels' tendency for Unstoppable Rage to the point that they'll do a FaceHeel Turn and start serving Khorne, the god of wrath. He apparently missed the memo that Unstoppable Rage is, well, unstoppable, and the infuriated Angels overrun his armies and get him killed before he's able to corrupt them.
In Vulkan Lives, Curze has Vulkan run through an ever-changing maze to the former's amusement, with the promised prize being a hammer with a built-in teleporter. Upon Vulkan finding the hammer, Curze shows up right in front of him to gloat about how the maze has anti-teleportation shields, and his teleporter is useless. Vulkan's response?
You forgot about one thing, Konrad... It's also a hammer.
In Deathfire, the ship the main characters are travelling on is infested by a gang of daemons which take form of little girls to lure people into close quarters, whereupon they eviscerate them. On their hit list is a pair of techmarines repairing an airless, gravity-less area between two layers of the hull. Some time into the incursion, the main characters meet with the techmarines, and the conversation goes something like this:
Numeon: There are daemons on the ship. They look like... Techmarine 1: Children, we know. We've shot one. Techmarine 2: We have realized there's something off when we saw it floating and talking to us without a void suit.
In the Jacob's Ladder Trilogy, Cynric the Sorceress apparently has a reputation for having failures as spectacular as her successes. While none are directly witnessed, Grail features a scene Mallory and Tristen quickly conclude that one particular disaster is not her fault because one of her screw-ups would have been a great deal more catastrophic.
Cynric did not make merely human errors. Her mistakes were more on the epic scale, her failings those of demigods.
In The Kingkiller Chronicle, Kvothe tries to convince the Eccentric Mentor Elodin to teach him the secret magic of Naming, to Elodin's mounting irritation. Eventually, Elodin tells him to go jump off the roof... which Kvothe mistakes for a Secret Test of Character and does. He breaks three ribs, dislocates his shoulder, and convinces Elodin that nobody as foolhardy as he should be let anywhere near Naming.
Elodin: Congratulations. That was the stupidest thing I've ever seen. Ever.
The Battle of Fondor in New Jedi Order: Agents of Chaos II — Jedi Eclipse. Bad intelligence predictions lead to the New Republic scrambling to respond to the Yuuzhan Vong invasion of Fondor. As part of the response, Anakin Solo takes control of Centerpoint Station (a Pointless Doomsday Device from The Corellian Trilogy), but then at his older brother Jacen's unexplained urging refuses to fire it (probably a result of the early books' poorly explained aversion to using leftover Imperial superweapons to fight the invaders). But the station is still active, so his cousin Thrackan Sal-Solo grabs the controls and fires it himself. The ensuing blast destroys half of the Yuuzhan Vong fleet, and the Hapan fleet that just arrived to reinforce the defenders, and smashes part of Fondor's moon, and clips the planet on its way past (cue Inferred Holocaust). The battle becomes a Pyrrhic Victory for the Republic (and that only because the opposing general withdraws in fear of further such attacks) and causes a political shitstorm in the Hapes Consortium that tips the balance of power to its Evil Matriarch Queen Mother Ta'a Chume, while the sudden death toll carried through the Force causes her daughter-in-law Queen Teneniel Djo to miscarry. Meanwhile Sal-Solo, who was the villain in his first appearance and did a stint in prison for an attempted coup against the Corellian system's New Republic government, is lauded as a war hero on Corellia and gets himself elected Governor-General (setting up part of Legacy of the Force). To cap it all off, Centerpoint Station is damaged to disablement by Sal-Solo's manhandling, and Anakin admits afterward that if he'd fired Centerpoint Station himself, he could have taken out the Vong fleet without causing all that damage.
In A Rising Thunder, the Solarian League sends several hundred of their most powerful warships to (they think) effortlessly curb-stomp Manticore after the Manticorans have suffered the twin setbacks of the Battle of Manticore and the Oyster Bay sneak attack, seriously depleting their military resources. Oh, someone gets curb-stomped alright... but it isn't the Manticorans. Or the rest of their Grand Alliance, for that matter.
David Weber's Safehold series features a triumphant example of this. The first book, Off Armageddon Reef, featured the Church of God Awaiting attacking the protagonist kingdom of Charis by creating an alliance of every single other naval power in the world. Unfortunately for them, thanks to Charis' own strong naval tradition coupled with Merlin Athrawes giving the galleon (among other things) to the Charisians, what actually happens is Fail so Epic it takes the Church two and a half books (a good two or three years in-story) to finally recover enough to make any kind of counterattack. That fails hard, too. Though not without a more sizeable cost from Charis' forces. Compounding their failure was the fact that most of the people planning the attack were accustomed to land battles and didn't take into account the realities of the weather, the limitations of the vessels they were using, etc. And one reason it took so long to recover is because they spent a good chunk of that building the wrong ships, as they were building a galley fleet after Charis' victories show how significantly galleons had come to outclass them as warships.
Shadow Games, book four of The Black Company, ends with the Company attempting to lay siege to the city of Dejagore. It goes so badly that the next two books deal almost exclusively with the Company picking up the pieces. It even results in the series' first change of narrators, because the original narrator is captured, but presumed dead.
There is a cookery book (called, logically, The Something Went Wrong What Do I Do Now Cookery Book) dedicated to correcting various kitchen emergencies. Naturally, it includes a chapter called "Total Failure". One piece of advice therein — if you've tried everything else, if you haven't got enough ingredients for an emergency meal and you have no other recourse, at least make it a memorable failure, one that will be recounted with awe through the generations.
"If you've burned the house down, Mission Accomplished."
The Way of Kings: When Kaladin discovers his Surgebinding powers, it takes him weeks to learn how to draw in Stormlight intentionally. He spends most of that time staring at spheres filled with Stormlight, holding his breath. You draw in Stormlight by breathing.
After Shallan is shipwrecked, she tries to use her Soulcasting abilities to transform some driftwood into a fire, and ends up arguing with a stick. And losing. It's still bothering her in Oathbringer.
Shallan: You want to burn. Stick: I am a stick. Shallan: Think of how much fun it would be? Stick: I am a stick.
Once Kaladin finally understands his Gravity Master abilities and tests changing the direction he can fall, he tries to run up a wall and lands flat on his face. On the wall, so that worked, but still.
In his commentary on The Tales of Beedle the Bard, Albus Dumbledore describes the attempt at Hogwarts to hold a production of "The Fountain of Fair Fortune." Unfortunately, Romance on the Set led to a fierce Wizard Duel when the male lead dumped one of the actresses for another—and while this was going on, an ashwinder was busy setting the place on fire. Hogwarts has not attempted any stage productions since.
The backstory for the Wayside School series is that it was supposed to be a single-story building, with 30 classrooms in a row. What was built was a 30-story building, with a classroom on each floor. The builder said he was very sorry. What's more, there is no 19th floor.
The short story "Wolfie" by Theodore Cogswell is supernatural thriller meets caper gone wrong. A man in New York City goes to a sorcerer for help in murdering his rich cousin. His idea is to take the form of a wolf and rip his cousin's throat out. There is a slip-up at the veterinary hospital he has tricked a wolf blood sample out of; they give him a sample from an old, toothless, mangy poodle named Wolfie by mistake. To make failure even more certain, as a precaution to protect the witch doctor from You Have Failed Me at the hands of his familiar should our Villain Protagonist get cold feet or a Heel Realization, the [the would-be murderer] cannot change back until he has tasted his cousin's arterial blood. In the end, he is put down by the Animal Rescue League.