A Hand Wave (also memetically called "Scotch Tape") is any flimsy explanation - particularly involving the backstory, a retcon, or a use of phlebotinum - which is noteworthy for its lack of detail or coherence. It may be used to (try to) hold together an Idiot Plot or an otherwise outrageous story. Often consists of throwaway lines like "It's the Only Way." The name comes from academia, initially to refer to where complicated parts of a valid argument are glossed over for the sake of convenience.
Sometimes this is simply because the writers couldn't think of a plausible explanation, so decided to play down its importance. In the best cases it's because the explanation is genuinely irrelevant to the story and would be a distraction. Sometimes it's because the thing they're handwaving is so universally reviled that they want to joke along with the audience's disdain for it.
In an adaptation, a Hand Wave can result from Adaptation Explanation Extrication - the writers removed the back story to a plot element, and then realized that someone needed to say something about it.
When skillfully done, a handwave can obscure the ridiculousness, or at least make it plausible enough so that the audience achieves a Willing Suspension of Disbelief. It can also just turn the whole detail and its inexplicability into a joke. Scotch tape may not be strong, it may not be pretty, but if you're striving to create an accurate piece of storytelling that aims to describe, it may be much better to have some sort of explanation than nothing at all. This is only the case, however, provided that dream logic or other tropes and rules do not work much better in the context.
The Watson is often a valuable source of Scotch Tape. In Science Fiction shows, a handwave is usually conducted with Technobabble. In fact, an alternate name for Phlebotinum is Handwavium.
In the industry, the vague and generic direction given by management to actors, designers, editors etc is sometimes known as "hand waving" as it is frequently accompanied by a lot of equally unhelpful gesturing. But that is not this trope.
See also A Wizard Did It. Compare and contrast Justified Trope. A.K.A. Scotch Tape (not to be confused with Duct Tape). May take advantage of the MST3K Mantra. Often related to an Unexplained Recovery. Not to be confused with the Jedi Mind Trick, which is often accompanied by a literal hand wave.
The lack of male-type humanoid robots in Yokohama Kaidashi Kikou is supposedly because of the male versions being "weaker" than the female ones, but how this difference comes about is never explained. And that's not the only thing in the manga that gets handwaved...
Naruto makes friends with the monster that's wanted to kill him for the entire series, a monster infamous for destroying landscapes and attacked the main character's hometown. It turns out that Madara and Obito Uchiha were the ones making the Demon Fox do bad things using their powers, and the Fox was an innocent, puppy-sized mutant animal until it grew up... literally, and garnered a reputation for being demonic.
Played (kinda) for laughs in Bleach in one of its filler arcs. When Renji's sword Zabimaru breaks free, Zabimaru is shown as a split being, a monkeyish woman and a childish snake. This is contrary to Zabimaru's previous appearance, which was an actual monkey that had a snake for a tail (a Nue). When Renji asks why Zabimaru isn't in its previous form, the Chimpett half of Zabimaru simply laughs and says, "Since when are you so concerned with minor details?" "That's a pretty big freakin' detail!"
Also in Bleach the main character getting stronger bafflingly (if not infuriatingly) fast is explained by - "Learning fast is one of his special abilities."
This is actually based on an omake when Renji and Hisagi read a catalogue of changes Mayuri can do to their weapons' true forms, Renji sees that changing them into females is possible. So it may or may not count.
Ulquiorra has stated that Ichigo's power is "in constant flux." Which kind of explains how he's stronger than certain characters but those characters are stronger than people who were able to completely annihilate him. This "flux" is actually why Ichigo gets his ass handed to him from time to time. Does not excuse the Villain Ball that happens afterward, gets a passing mention, and you can count on your fingers how many plots this affected.
The Future Arc in Katekyo Hitman Reborn! recently concluded with the Acrobalenos performing a huge Reset Button so that Byakuran never gains the power of the Mare Rings when the inevitable Time Paradox is pointed out by Shoichi, Verde's response was simply that the existence of the Trinnisette amounts to a miracle by itself and can't be explained by science or common sense
Haruhi Suzumiya. Haruhi damn it, Tanigawa Nagaru, he deliberately makes the Esper, Alien, and Time Traveller members say they don't really know how their upper structure works to justify their status, which sometimes gets rather ridiculous.
Eiichiro Oda, maker of One Piece, is famous for giving very strange explanations when the fans ask him about the show, like saying that Zoro can talk with a sword in his mouth because his heart allows him to. Or that Sanji's leg is perfectly unharmed after being intensely heated because 'his heart burns hotter.' Given that the entire world of One Pieceruns on Nonsensoleum, these explanations (as ridiculous as they may be) are also literally true.
In Oda Nobuna No Yabou, its never clearly explained how Sagara Yoshiharu not only traveled back in time, to around the Sengoku period in ancient Japan, but many of the major people he remembered as old guys are instead young women. And the one guy who saves his life at the beginning was Toyotomi Hideyoshi, who is conveniently killed off, and tells the young lad to take his place and help Oda Nobuna to achieve her dreams of uniting Japan.
Batman: He does not have any super powers but he does have super intellect, peak level human ability, and is unequalled as a detective, fighter, inventor, scientist, strategist, and whatever else the plot requires him to the the best at. He is also one of the top three wealthiest men in the DC universe. Batman also has a backup for every backup for every backup et cetera. Alfred the butler also seems to also be everybit the universal polymath being a medic, mechanic, technician, spy, actor, and occasionally a butler.
Scrooge McDuck has always been known for swimming in his money. In the Carl Barks story, "Only A Poor Old Man", the Beagle Boys manage to legally get his cash, leading Scrooge to lament how he won't be able to indulge in his hobby. After giving a demonstration, the old duck offers that the Boys try it themselves. The Beagles dive in, and immediately knock themselves out on the pile of coins. When Huey, Dewey and Louie bring up the Fridge Logic, Scrooge remarks, "I'll admit- It's a trick!"
The Flash has the Speed Force, a dimension that is also apparently a prison and a mass vaporizer. And just an all-around way for speedsters to tell the laws of physics to sit down and shut up. It was also a way to explain how an increasing pool of characters were randomly struck by lightning in front of a wall of chemicals.
Probably not attributable to the original creators, but a Finnish Superman magazine once answered the question in reader mail about how Superman can fly: It's just like how we walk. He activates the muscles used for flying. And now you know!
In The Prayer Warriors, during his first encounter with Percy Jackson, Jerry, the main character, realizes that there is a traitor among the Prayer Warriors, and spends the next few chapters trying to figure out who it is. It's revealed, midway through this process, that God told him that there was a traitor the night before the attack, but God apparently neglected to mention who the traitor was.
Kuzco: No! It can't be! How did you get back here before us?
Yzma: [!!] ...How did we, Kronk?
Kronk: Well, ya got me. By all accounts, it doesn't make sense.
Films — Live Action
In The Wizard of Oz (1939 movie), Glinda waits till the end of the movie to tell Dorothy about the ruby slippers. Why didn't she tell her at the beginning, instead of sending her Off To See The Wizard down the Yellow Brick Road? "Because you wouldn't have believed me." This covers up a plot hole caused by merging two different Witches from the books.
In Batman Begins, Batman (who has a strict no-kill policy) gets into a high-speed chase on the freeway with the cops, causes more than a couple crashes and drives over several cop cars with the cops still inside, endangering dozens of civilian and police officer lives. Yet we know no one is hurt (very badly) because Alfred says: "It's a miracle no one was killed." The same thing happens in The Dark Knight, as he fires high-powered guns into what appears to be a mall's glass door to break it so he can drive through, then showing people dodging out of the way. No way someone wasn't going to get hit. In The Dark Knight, it is "explained" that the Batmobile has "life sign scanners."
In the film The Abyss, the pressurized station so deep underwater that it can cause illness to people on board is brought to the surface in the space of less than a minute, and immediately people climb out, without having any symptoms of 'the bends.' Lindsey defuses a Fridge Logic moment by saying "We should all be dead. We didn't depressurize," and another character answers "[The aliens] must have done something to us." No further explanation is given. The novelization (by Orson Scott Card, no less!) handles this a bit better...holes such as this (and the alien's back-story) are filled in fastidiously. All without diminishing the mystery and wonder.
Played for comedy in Big Trouble in Little China when Egg Shen appears above a hole in the ceiling. Jack asks how he got up there, and Egg simply replies, "Wasn't easy!"
At the end of Part II, the DeLorean gets struck by lightning while flying, and gets sent to 1885. At the point when the lightning actually strikes the car, it is stationary in the air, but it has to be moving at 88 miles per hour to time travel (which is important in both parts I and III). When it got hit it wasn't moving. The handwave is that the lightning causes the DeLorean to spin at 88 miles per hour, shown with the trails of fire being spirals in the air (the 1885 date is justified, as the time circuits were shown earlier to be broken, and an 1885 date was briefly shown).
The letter that Doc Brown sent in 1885 to Marty. The idea that anyone would follow through with instructions to send a letter to someone 70 years in the future with exact location and time is a little tough to swallow; the guy just explains that they were taking bets down at the Western Union whether Marty would be there or not.
Note that spacecraft never use an all oxygen environment as there was actually a fire aboard Apollo 1 as it was sitting on the ground that was unable to be stopped due to the all oxygen environment. As a result three astronauts were killed.
In the book Harry Potter and the Half-Blood Prince, in order to travel to a plot-important location, Harry and Dumbledore must sneak out of the school to a completely deserted street in a nearby village, from which they can then Apparate. In the film, the following time-saving exchange occurs:
A reasonable interpretation would be that he wrote the spells involved, so he left himself a backdoor.
In the book, Dumbledore simply reverses the spell over Hogwarts preventing Apparition first, they replaces it behind them after they're inside.
In the film Ocean's Thirteen, to explain the absence of series regulars Julia Roberts and Catherine Zeta-Jones, Danny Ocean (George Clooney) repeats the phrase "It's not their fight!" numerous times within the first ten minutes of the film.
In the Sherlock Holmes film "A Study in Terror", Holmes is trapped in a burning building. They quickly cut to him back at Baker Street, explaining that he survived because, as everyone knows, he's indestructible. Shades of the Master (see below)!
Pirates of the Caribbean: Whenever something improbable happens, the character (usually Jack Sparrow or Captain Teague) insists Sea Turtles were involved.
Lampshaded in Jasper Fforde's Thursday Next series; a "textual sieve" is apparently some sort of book security device, but it is never very clear exactly what it does. At one point, a character asks Thursday just what it is, and she replies, "It's never fully explained."
In the children's science fiction novel I Left My Sneakers in Dimension X, the main character is transported to Dimension X. Shortly after finding himself able to communicate with one of the locals there, he asks how he speaks his language. The local responds that the opposite is happening and the protagonist is speaking the language of Dimension X, which he quickly realizes is true. The explanation given is a quick bit about cross-dimensional travel's effect on the mind, and is never brought up again. Nor is it really a very good explanation, if someone from Dimension X came to our dimension, what language would they speak? (Considering in the series it includes not only the hundreds of languages on Earth but also alien ones.)
It's stated that you have to "cross dimensions in exactly the right way", and that the monster that brought the protagonist there is "a perfectionist". Presumably, if you cross precisely, you can rearrange someone's brain in just the right way that they start speaking a different language. Telepathy, which appears into the series a lot, is probably also involved. It's still a major Hand Wave, but at least you could say that it's the work of the one creating the dimensional bridge, rather than a natural effect.
In one of Harlan Ellison's short stories, he has the protagonist trapped in a situation that, judging by the description, there is absolutely no way he could logically escape. The author then stops the story to tell us that the protagonist remembers a time he once bought a pulp novel that ended with a Cliff Hanger in which its hero was likewise trapped in a seemingly inescapable situation. When the next chapter finally arrived, he very eagerly snapped it up, only to discover that it tied up all the stuff left hanging in the last episode in the first sentence by turning the hero into an action figure and having him punch his way out of the trap. Getting back to the story, the author then tells us the protagonist was still thinking of how cheated he'd felt about that pulp novel's hand-wave—when he finally escaped.
In Robert Heinlein's "The Rolling Stones", Hazel is writing a television show and got herself into this exact problem. Her grandson suggests this exact resolution, suggesting that the season opening episode start with the hero back in the office perfectly healthy, and is about to respond to another character's question "How did you escape?", when "they are interrupted by action which is so fast and exciting that the audience won't remember the question until the next commercial break".
In Jack Finney's short story "Behind the News", a newspaper man uses a melted-down meteor made of an unknown metal to make his news come true (kind of like the Twilight Zone episode "Printer's Devil"), and when his secretary doesn't understand how it's happening, he gives the following explanation:
"Miss Gerraghty," Johnny said sternly, "if you had ever read science fiction, you'd know that the dullest part is always the explanation. It bores the reader and clutters up the story. Especially when the author flunked high-school physics and simply doesn't know how it works."
There's never any danger of the international intrigue in the Ender's Game series erupting into a full-scale nuclear war because, as Peter Wiggin explains in a throwaway line in the first book, the invention of energy shields has made nuclear weapons obsolete.
Although later in the Ender's Shadow subseries, it is further clarified that the International Fleet, while normally neutral toward Earthside conflicts, will severely punish any nation that uses nukes.
A criticism of Agatha Christie's Hercule Poirot stories is the way the mysteries are sometimes solved. It relies either on a one in a million chance that Poirot's interpretation is correct or Poirot knows something without going into how he knows it with Poirot hand waving the whole thing with "I have my methods."
In Percy Jackson and the Olympians, demigods frequently date each other. Since all demigods' godly parents are related, that would mean demigods are all related and that any dating between demigods would be incest. But it turns out gods don't have DNA, meaning that demigods aren't related and it's fine for demigods to date each other. As long as the members of the couple don't share a godly parent.
Live Action TV
Anything involving Dawn as the Key on Buffy the Vampire Slayer. And any time when someone explains why the main problem of an episode just can't be resolved using a simpler spell or plan. Anya later lampshaded it. When someone mentioned the part about Buffy's blood working as a substitute for Dawn's, she says something to the effect of "Yeah, I never got that part."
An early episode of Star Trek: Voyager has the crew needing to conserve power. Yet they still wanted the characters to play around on the holodeck. So they threw in a line about how it's power systems are self-contained and cannot be used by any other system on the ship.
In "Trials And Tribble-ations", several Deep Space Nine crew members (including Commander Worf) travel back in time to an episode from Star Trek: The Original Series. They remark on the difference in appearance between Worf (with his elaborate makeup and appliances) and the smooth-headed Kirk-era Klingons (with very simple makeup). Worf puts them off, saying, "We do not discuss it with outsiders". Eventually it is retconned in Star Trek: Enterprise as the result of some earlier botched attempts to create genetically "augmented" Klingons.
The transporters include a component called a "Heisenberg compensator" as a handwave to get around quantum uncertainty effects. Michael Okuda (one of the designers of Star Trek, starting with the fourth movie) got around a question during an interview for Time Magazine about how it works by answering, "It works very well, thank you."
In Farscape, the explanation given by Crichton at one point as to how a ship equipped with 'hetch drive' is able to travel faster than light is that "Einstein was wrong" which, for a bit of handwaving, is actually quite clever.
The sonic screwdriver is a small handheld device capable of performing almost any task needed to get the Doctor out of a (often writer-induced) jam, from diagnosing injuries to locking/unlocking doors, hacking computers, blowing up security cameras, and, yes, even turning screws (well, one). The device works by flipping a switch and waving it at the intended target. Overuse caused the screwdriver to get removed from the classic series, but it was brought back and significantly strengthened in the new run. To compensate for its increased usefulness, they introduced a Kryptonite Factor in the "deadlock seal," which cannot be opened by sonic screwdriver. Oh, and it doesn't do wood.
Its "point it at something and it does whatever you want it to" nature was recently explained as it being able to work psychically. You point it, think of what function you want it to perform, and press the button. Sort of a way to save on-screen time, since the Doctor doesn't have to re-adjust it every time he wants it to do something different.
The Master's return from certain death (being burned alive in "Planet of Fire") is completely handwaved when he next appears in "The Mark of the Rani". When asked how he survived, the Master simply replies "I'm indestructible. The whole universe knows that." And that's the end of it. No explanation is even attempted onscreen. (There's a very brief, rather unconvincing one in the novelization, though.)
The TARDIS is semi-sentient and has long-range telepathic connections with the Doctor (as evidenced by the translation field). Not only that, in the new show the sonic screwdriver is increasingly connected to the TARDIS, to the point of the latter's "regeneration" with the 11th Doctor popping up a new sonic screwdriver in the control panel. Somehow these facts do not turn it into more than a very basic remote control (it can lock\unlock the doors) or ability to summon the TARDIS to the Doctor's current location, whether by flight or materialization.
Of course, the Tardis would be far too complex to fly remotely using a screwdriver....
In Lets Kill Hitler, a freshly regenerated River Song suggests to herself "Maybe I'll dial back the age a bit. Gradually. Just to freak people out." as a handwave for why she appears to be getting older even though her timeline and the Doctor's are reversed.
This is a case of handwaving arguably being unnecessary. It had only been about 3 (real world) years since her first/last appearance, so she actually didn't look any older.
The perception filter, which either acts as a disguise or (more usually) prevents people from noticing you. It's now being used as the excuse for the monster of the week to be able to hide from everyone all the time. The writers at least had the grace to lampshade this in an episode where when everyone fails to notice for ages that they're on a planet of two-headed aliens and all the statues have one head, when the Doctor declares that it's either a perception filter, or they're just all idiots.
The psychic paper was explicitly devised by Russell T. Davies to facilitate this; it can show whatever the person holding it wants the person reading it to see, meaning that the Doctor could explain what he was doing in the room where he shouldn't be or why he might have been found over a corpse quickly and bluntly without having to hold the plot up however many episodes until it all got sorted out.
"It's a 'Fixed Point in Time' " is one of the go-to handwaves to explain why the Doctor doesn't just use his time machine to fix any problem or undo any tragedy.
There is a Swedish reality show called Lyxfällan. Rough translation: "The Luxury Trap." The show deals with regular people with severe financial problems, usually from living a luxurious lifestyle that they cannot afford. The hosts of the show try to help these people, not by giving them money, but by helping them analyse their financial situation, selling off valuable things and making deals for paying off their debts and such. The goal is to get them back on their feet and save them from bankruptcy. One episode featured a woman who had not paid her bills in eight years! When asked why the hell not, she hand waved it by explaining that the payment of bills was not a part of her life. In this case though, ADHD is a possible reason why she is not able to handle her economy, which makes the viewer feel somewhat sympathetic of her. Most of the other people on the show, however, are either Too Dumb to Live or an example of exactly why you shouldn't ignore a problem with the hope that it will just go away.
In Babylon 5, one common statement is that no Minbari has killed another Minbari since Valen's time. But in a season four episode, Marcus challenges Nehroon to a battle to the death under the Minbari ritual of denn'sha. Since Nehroon immediately knows what it is, that implies that the Minbari have been killing each other in formal duels for quite some time, despite this 'Minbari do not kill Minbari' principle. In one of the books they hand wave it by saying that by agreeing to fight a denn'sha duel, you agree to take responsibility for your death on your own hands if you lose. This means that every single Minbari who died in a duel has technically committed suicide, which doesn't count.
In The Man from U.N.C.L.E.., one of the innocents involved in the Affair was concerned that Solo was killing so many enemy agents, he explained that they used "sleep darts" in their guns.
In Cheers, Frasier Crane mentions that his father is dead, and was a research scientist. Fast forward to the Spin-OffFrasier, and Martin Crane is an ex-cop and very much alive. The writers explain this away when Sam Malone visits Frasier and points this out, by having Frasier admit he was actually lying, as he'd just had a fight with Martin offscreen when he said that. Marty, on the other hand, is just insulted he made him a ''research scientist'', as he feels it shows Frasier's snootines toward his working-class job.
Frasier: You were dead, what did it matter?
Parodied in the "Cycling Tour" episode of Monty Python's Flying Circus. Gulliver and Pither are about to be bayonetted by a group of Russian soldiers. Just as the soldiers charge, a "Scene Missing" slide appears on the screen. Immediately after that, they cut to Gulliver and Pither on a road in Cornwall, with Pither saying, "Phew! What an amazing escape!"
In Sabrina the Teenage Witch Season 2 episode 16 Zelda pulls a periscope down from the ceiling, to which Sabrina reasonably asks "Since when do we have a periscope in the kitchen?" Hilda replies with "You've lived here two years and you've never noticed it? Teenagers."
In the episode "The End of the Whole Mess" in Stephen King's Nightmares and Dreamscapes series of TV movies, Howard Fornoy hand waves the issue of how he and his brother raised the vast amount of money needed for their experiment in such a short time. Justified in that an explanation would kill the story's momentum, the narrator genuinely doesn't have time to go into it and nobody really cares.
In-universe in the "Popilikia" episode of the reimagined Hawaii Five-0. At the end of the third-season premiere, three episodes earlier, we'd seen McGarrett's mother, Doris, whom he'd only recently learned had actually faked her own death twenty years earlier, in a confrontation with the show's Big Bad, Wo Fat, who wanted to kill her in order to avenge his own father's death. The ballistics report showed that she had fired three shots into the floor, apparently allowing him to escape. She explained in the later episode that those shots were simply the result of a struggle between her and Wo Fat. McGarrett apparently accepted it, but later he confided to Danny that he did not.
The Supernatural episode "Hello, Cruel World" established that Leviathans can assume the forms of humans they've come in physical contact with, and doing so grants them all the knowledge and memories of that particular human. However, in "The Girl With The Dungeons And Dragons Tattoo" when the Leviathans needed Felicia Day's character to extract information from a hard drive for them, it was revealed that certain humans have a "spark" to them that the Leviathans can't replicate. This was presumably done to avoid the question of why they didn't just kill her, steal her memories, decode the hard drive themselves, and avoid the inevitable Heel Face Turn.
On Fringe the original Peter's death required a rather huge handwave, since the entire premise of the series pretty much revolves around nobody realizing that Walter replaced him with the Peter stolen from the alternate universe. The fact that nobody except a handful of people realized the original Peter was actually dead was explained away by the idea that young Peter was so sickly that he was always kept indoors, never went to school and had few friends or visitors. Nevertheless, a burial service was shown (with the mourners consisting only of Walter, his wife, Nina Sharp and the priest) and a headstone for Peter did exist. Why the FBI never managed to discover on a routine background check (when the redverse Peter was hired) that Peter Bishop died in 1985 remains a mystery.
Two in the Stargate SG-1 episode "Ripple Effect." First, Dr. Lee asks why all the teams coming in from alternate universes are SG-1; Carter explains it away as SG-1 being the front-line team and most likely to get into trouble offworld which would make the SGC more likely to let them through. Soon after, Dr. Lee mentions offhand that the proximity of the various universes to each other accounts for the lack of "entropic cascade failure" that previously occurred when an alternate Carter came to the SGC.
A certain Game Genie code for Super Mario Bros. 3 causes the game to freeze after you defeat Bowser in Dark Land. The Game Genie manual states that you must press Up at the final door straight away, otherwise you may get caught in Bowser's time trap and the game will pause forever. Nice way of masking a cheat code glitch, guys...
In Final Fantasy VIII the Big Bad Ultimecia wants to force the world to go under "Time Compression." Infuriatingly to many players, when the question of what her motive is in doing this is handwaved away by the mad scientist Odine as "Who knows? It does not matter." Thanks to some cryptic statements made by Ultimecia in the final battle, all sorts of theories have been suggested regarding her motives, including the popular fan theory that she is actually the future version of Rinoa (a theory Jossed by Word Of God). Ultimecia's reasons for undergoing time compression are explained throughout the game. Officially, she was trying to destroy time as time had unfairly painted her as a villain (this is in fact supported by the script throughout the game as well).
Sephiroth's motivations stem from wanting to become a deity, but the exact mechanisms he's planning to use for this are just as hand-wavey. Not that bad, since Biologically Sephiroth was actually more Jenova than Human at the time. Everything he did does make sense, with that knowledge.
The video game Deus Ex has lockpicks and multitools that, for some unexplained reason, can only be used once. During the tutorial level your support says that "unlocking doors expends the resources of modern lockpicks", but seeing as how the actual item is just two rods that spin about, it doesn't make much sense. It's never mentioned why the multitools can only be used once. Maybe they used really cheap batteries?
The Hand Wave is actually that the actual lockpick mechanism is significant nanite swarms that attempt to mimic the lock combination - depletion of those is what causes lockpicks to deplete. As for multitools, there's no explanation but it's easy to assume that a catch-all tool made to hack any and all tech in a Twenty Minutes into the Future high-tech game world would require a lot of juice. The damn things shouldn't be disposable though. It'd be like throwing away an iPhone after every call.
A better Handwave would be that you're actually carrying only one lockpick and one multitool, each of which has a certain number of "charges" (up to ten); you're never seen putting one away and getting out another even on locks that require multiple uses. Thus when you pick up an additional device, you really just take the batteries out of it and use them to recharge your tools.
In the first three games in The Elder Scrolls video game series, the nation of Cyrodiil is described as mostly tropical jungle. Oblivion is the only one that actually takes place there, and it is shown to actually be mostly temperate hardwood forest. The in-game books "Commentaries on the Mysterium Xarxes" vaguely explains that the god Talos (the endivinated spirit of the first Cyrodiilic emperor) used his powers to make Cyrodiil colder to make the local soldiers more comfortable.
This inconsistency was supposedly brought up in an interview with one of the devs of the game, whose response was rather hostile and went along the lines of "Are you really going to complain about esoteric information located within the backstory of the backstory?"
The reason the Kajiit look different is explained by there being various species which are dependent on the phases of the moons, from certain species looking like massive lions and used as sentient mounts to others barely different from Bosmer, with whatever is seen in game being the most common in that province.-
The manual of Sonic 3 handwaved the game's physics bugs as just part of the "many diabolical traps" created by Dr. Robotnik.
In BioShock, the research camera analyzes the creatures you photograph and will give you "research bonuses" towards greater damage. Atlas explains this with a lot of five dollar words, but it still doesn't eliminate the fact that it's just a camera.
An even bigger hand-wave of the same stripe comes in the form of the Camouflage Tonic, discovered by research-photographing the disappearing-reappearing Houdini Splicers. That's right, kids, all it takes to engineer an advanced tonic that allows you to go sight unseen is a few handy snapshots! Grab those cameras and do Andrew Ryan proud!
The Vita-Chambers handwave Bioshock's system of allowing the player to respawn at the instant of his death, with opponents retaining the damage you have already dealt them. Not that it does Ryan any good later on. He did state that he has disabled the nearest Vita Chamber before letting you in to see him. Perhaps it does have an effective range.
The existence of villain Sophia Lamb in the sequel is justified by a Hand Wave. Lamb's a brilliant psychiatrist, smart and eloquent enough to best Andrew Ryan in public debates and charismatic enough to assemble a cult. Why did we play through the first game without the slightest hint of her existence? There's an audio recording in the sequel where Ryan tells his security chief to go beyond just imprisoning Lamb: he wants her wiped from the history books. Problem solved.
After completing Metal Gear Solid 3, you get The Boss's gun if you start a New Game Plus. If you equip it and call your weapons expert, he asks how Snake has it, and Snake tells him not to worry about it. He also tells Snake that the gun has infinite ammo because the ammo feed is shaped like an infinity sign. "Makes sense..."
At one point, Snake can eat some Bio-Luminescence Mushrooms in a cave, they recharge the batteries of all your electronic objects. When you speak with Para-Medic about this, she says that it's impossible for that to happen. When Snake proves to her that it happened, she says that it must have been the placebo effect.
The Legend of Zelda: The Minish Cap seems to be, at least in part, Nintendo's attempt to do more than simply Hand Wave the fact that Link is able to find money in random bushes and patches of grass, by explaining that the tiny race of people known as the Minish like to scatter the money for big people to find.
They also scatter bombs, arrows, and hearts, and may be responsible for some of the ubiquitous treasure chests.
In the original Street Fighter, players fought an enemy named Birdie, who was a white punk with a mohawk. When the character returned in Street Fighter Alpha, he was a huge, hulking, black punk with an even bigger mohawk. In Street Fighter Alpha 3, he claims in one of his win quotes, "I looked pale because I was sick."
Due to lazy programming in the first two The Legend Of Zelda C Di Games, you interact with all objects in the game world by hitting them with your sword. This also includes the NPCs which you can start a conversation with by stabbing them. This is hand-waved in the in-game tutorial:
Link: Luckily I brought my Smart Sword. It won't hurt anyone friendly. In fact, it makes them talk!
World of Warcraft pulls a bit of one in the justification for why the Gnomes had failed to retake Gnomeregan for four years and the Darkspear Trolls had failed to recapture the Echo Isles, despite each being held by an elite boss capable of being killed by low-level players. Apparently, the thousands of Thermaplugg's and Zalazane's heads turned in by players over the years were all from fakes, not the real deal.
Remnants Of Skystone vaguely attempts to justify why the player missions could surely be done by the Rooks, Nidaria's standing army (who are even just dressed better to take on monsters than you), with a description that says they employ freelancers when they can't wait for the Rooks' ponderous command structure to swing into action, and with individual Rooks in the levels telling you that they wish they could accompany you, but they have orders to remain at their post.
Superman 64 is an odd case of having two different plots before release, and both were handwaves. The games original plot was that Lex Luthor was spreading Kryptonite Fog all over Metropolis, which was clearly a clumsy attempt to explain the game's ridiculous amount of fogging (a common trick used in early 3D games to prevent framerate dips). Later, the story was changed to Lex Luthor trapping Lois Lane and Jimmy Olsen in a virtual reality version of Metropolis, which handwaves not only the fogging but every other problem with the game.
Kid Icarus Uprising has a particularly funny hand wave regarding Pit not wanting to take his clothes off in the Hot Spring, as seen in the trailer.
Not to mention, in Chapter 5:
Pit: What's an Exo Tank doing here anyway?
Pandora: I wanted to get my driver's license. So I whipped up a little parking lot to practice in. But then it hit me. How am I supposed to steer without hands?
"Please. I always carry a Swiss army knife and a coil of wire."
Best part? The Foglios are making fun of this trope. It's not actually Agatha who's pulling that stunt, but a fictional Agatha on a radio show broadcast by the in-universe Foglios. And each of these segments is cut short by the "real" Agatha smashing her way into their studio to have a few words with them.
Later on, Othar Trygvassen, GENTLEMAN ADVENTURER gets what appears to be a back-breaking injury from a Jagermonster. Not a comic later, he is back on his feet and punching said Jagermonster like nothing happened. He explains his recovery with "Special trousers. Very heroic."
Captain Broadband dies at the end of issue two when killed by his own explosives device. By issue three he is back without explanation, save a small editor box stating clearly 'Captain Broadband died last issue' with no further explanation.
What the Fu's preferred way of explaining things. The characters just roll with it.
Lampshaded in Keegan's Truck 5, when Commander Canada repeatedly dodges Keegan's questions on how the former is alive despite being killed years ago (repeatedly insisting that it is irrelevant), culminating with this exchange:
Keegan: What are you hiding? Why can't you tell me? Commander Canada: I can't tell you why I'm still alive because the author is too lazy to come up with anything! Let it go! Keegan: Oh. Okay. Commander Canada: Now, back to the damn story.
Project Million: Spazz tries to figure out how The Wire escaped her TV. She throws several explanations at him such as she's not there and that he's in a dream within a dream, before claiming she "crawled through a river of shit and came out the other side clean".
The in-universe explanation for the SCP Foundation deleting Mary Sue entries that nobody liked? The article was infected with SCP-732, a.k.a. the Fanfic Virus, and the actual SCP was something else entirely.
The Aeon Flux episode "Reraizure" deals with the fate of creatures called "Narghiles". Since they're dangerous, one character decides to get rid of them, but because "You can't kill them" (those were his exact words and the only explanation given), he plans to put them all on a platform that will be shot into space.
Creator example: writers for the Justice League Unlimited episode "Epilogue" state that part of the reason they wrote the episode's events - revealing Terry McGinnis to be Bruce Wayne's biological son - was them realizing both him and his brother Matt have black hair, which looking at their parents (Mary is a redhead while Warren has light brown hair) is genetically improbable, a very clever way of handwaving any inconsistencies said reveal may create.
Stewie: Say, Brian, now that I think about it, how can you possibly have a thirteen-year-old son when you yourself are only seven? Brian: Well, those are dog years. Stewie: That doesn't make any sense. Brian: You know what, Stewie? If you don't like it, go on the internet and complain.
Brian: So why did they film that scene live? Stewie: Convenience. Brian: Yeah, but- Stewie: Let's not start pulling threads on this one.
A few Simpsons episodes use this trope. In "Homer's Barbershop Quartet", after Homer tells Bart and Lisa about his barbershop quartet, the kids have some questions about why they'd never heard about it until now, where all the money went, and so forth. Homer assures them that "there are perfectly logical answers to all those questions, but they'll have to wait for another day".
One of their questions ("When did you write a song?") was answered in the 11th season episode "That '90s Show".
One is made explaining the appearance of Frank Grimes, Jr.:
Homer: Wait a minute, Frank Grimes wasn't married!
Junior. He happened to like prostitutes, okay?
One episode of X-Men: Evolution has Wolverine telling a story of how he fought in World War II alongside Captain America. When asked by Professor X how he remembers this in spite of the face that he has such profound amnesia, Wolverine Hand Waves it by saying he remembers bits and pieces of the recent past while everything else is a blur.
Robot Leela: We're robots and we're in love. Let's ditch these meat jackets. (strips out of her mutant skin, revealing a Terminator-like exoskeleton) Robot Fry: Whoa, cool! (takes off his human skin to show a similar exoskeleton, then speaks in a matching voice) Hasta la vista, wiener! Robot Leela:(also in a Terminator voice) We'll be back... for our stuff. (The two robots leave.) Amy: Why did their voices change? Farnsworth: That's the one thing we'll never truly understand.
One funny example is from the episode "The Deep South". Dr. Zoidberg makes a new home inside a giant conch shell in the ocean. Later on, hilarity ensues when it is destroyed through likewise impossible means.
Zoidberg: My home! It burned down! (sobbing) How did this happen!? Hermes: That's a very good question! Bender: So THAT'S where I left my cigar. (Retrieves the cigar, puffs on it.) That explains everything. Hermes: That just raises further questions!!!
A great deal of Futurama's plot points are hand waved. Usually done through Professor Farnsworth, usually played for laughs, and usually raising way, way more questions than they answer. Of special note is the episode Clone of My Own.
Cubert J. Farnsworth: That's impossible! You can't go faster than the speed of light.
Early South Park episodes described the "Terrance and Phillip Show" as a cartoon with crappy animation, though this later evolved into a weirder (but funnier) premise that the show was actually filmed in Canada, where everything actually was crappy-looking. In the episode "Behind the Blow," which parodied VH-1's "Behind the Music", this inconsistency was waved away with a rather convoluted explanation. Apparently, in the South Park world there used to be a Terrance and Phillip cartoon that was separate from the live-action show, but the cartoon was so popular many people became confused as to whether or not T&P were real people or cartoon characters.
In The Adventures Of Jimmy Neutron Boy Genius episode "The Junk Man", Sheen asks Jimmy several questions as they are flying to and from the Moon, like why the voyage takes only a few minutes and why the boys don't need space suits and helmets. However, both times Jimmy starts to answer Sheen's questions, the camera cuts to Carl on the other side of the rocket singing an off-key, made-up song about the Moon. Both times Carl finishes singing, the camera cuts to Jimmy asking Sheen if he understands his answer and Sheen responding that he is still confused.
In the Invader Zim episode "The Frycook What Came From All That Space", Sizz-Lorr's very appearance is lampshaded by Zim of all people. The handwave comes in with Sizz-Lorr's response.
Sizz-Lorr: After your escape, the great Foodening began! Foodcourtia's most horrible food rush, that lasts twenty years! The gravatational pull from all that snacking makes it impossible for anything to leave the planet. I was trapped. Alone. Without help.
In The Legend of Korra, Amon debends his victims by bloodbending them. It isn't explained any more that that, the characters even say "somehow", with Tarrlok saying that he had no idea how he did it but it made sense considering how powerful a bender Amon/Noatak was.
It makes sense if you consider classical Chinese understandings of biology, which have Blood and Chi as being intricately linked with one another. Chi was explicitly the root of Bending power in the Avatar-verse, so with the strong influence of mythic Chinese concepts on the series, it would make sense for Bloodbending to be able to block bending permanently.
In "Baby Cakes", Applejack wonders how come Mr. and Mrs. Cake, who are earth ponies, managed to give birth to fraternal twins who are a pegasus and a unicorn. Mr. Cake hastily explains that he has a distant relative who was a unicorn, and his wife has a distant relative who was a pegasus, then nervously adds "That makes sense, right?"
In dreams, if you are aware enough to spot an inconsistency, your mind will Hand Wave it with the first explanation it can think of (which can be even more implausible than the original fact) to prevent you from waking up. And you will perfectly accept it. Then, when you wake up, Fridge Logic will come to you. In lucid dreaming, things that are out of the ordinary or impossible are called Dream Signs.
A person whose brain's lobes have been separated makes for interesting experiments. Essentially, each eye now reports only to half of the brain and each half is operating somewhat independently. Show one eye a card telling the person to do something (get up and get a Coke, say) and the person will then do so with no memory of having read the card. Ask why he did that and (presuming it's the other lobe controlling the mouth) he'll begin inventing more and more fabulous explanations for why he did so, even when he's shown the card with both eyes. Freaky.
It gets freakier. Severing the corpus collusum (part of the brain that connects its two hemispheres) which formerly was done to prevent epileptic seizures, can lead to alien hand syndrome. Each hand, like the eye, is controlled from the opposite hemisphere. So when they are separate, the left "rational" hemisphere is not in control of the left hand, but rather the right "emotional" hemisphere is. This had led to the right hemisphere and left hand essentially becoming mentally ill. One case had a man whose left hand would unbutton his shirt once the right hand had buttoned it up. Even more extreme are the cases where the right hemisphere is violent. One patient had to sit on his left hand or it would attempt to attack people. In other cases, it may be suicidal (possibly an inspiration for Dr. Strangelove, where the titular character had to stop his hand from going into a Nazi salute, or attempting to strangle him).
Even when the brain is whole, people are capable of awesome hand waves. When confronted with moral decisions, people make them almost instantly (unless they're really tough, like whether it's okay to sacrifice four people to save five others). Essentially, three things happen when we make a moral decision. One portion of the brain feels empathy for those involved (oh, wook at da baaybeees). Another portion of the brain seeks a much more utilitarian solution (kill the spares, collect all the food, live as a king). Depending on how strongly these two fire, we reach a decision, usually some kind of balance between the two. Then the final act happens; our prefrontal cortex (the part of the frontal lobe responsible for, among other things, logical thought) justifies the decision we've reached. In other words, all those books you had to read in philosophy 101 about morality and the justification for various ethics? So much handwaving for decisions stuffy German men had already made. But very, very sophisticated handwaving.
Though, to be fair, it takes quite a lot of handwaving for biologists to reach a conclusion like that.
One way people reduce cognitive dissonance (a difference between our actions — say, driving an SUV — and our beliefs — say, environmentalism — which causes some discomfort) is by rationalising their actions. This rationalization often takes the form of handwaves ("If it wasn't me driving this SUV, it'd be someone else, and I use public transport when I can."). Often if you give these explanations to other people, they'll point out just how flimsy they are. Unless they agree with you, in which case they'll tell you how rock-solid your logic is.
This often happens in political discussions. Alice supports Politician X because he is a member of her preferred party. Bob points out that Politician X is corrupt and supports policies that conflict with Alice's morals. Alice invents reasons why Politician X's controversial actions aren't actually that bad, and he's still better than Politician Y.