Thorkell from the manga Vinland Saga, defects from the Danish army to align himself with the English because he thinks it would be more fun. Afterwards, he decides to become the vassal of Prince Canute, the clear underdog in the competition for the Danish throne, as if he did not have enough to fight against to begin with. The man is a huge, Older Than He Looks, man's man of a warrior, so it is almost expected.
Light, the villain protagonist from Death Note briefly mentioned that it was too easy and no fun just leading the Kira investigation team around after he offed L. Enter Near and Mello to rectify that. Eventually.
Yusuke Urameshi from YuYu Hakusho falls victim to this after he wins the dark tournament, although he is then punished for his complacency as the next arc starts with him getting kidnapped. It then happens AGAIN after beating Sensui, because being an S-rank demon leaves him as the most powerful fighter in the human world by miles.
Tengen Toppa Gurren Lagann: After Simon defeats Lord Genome, the people build a city and the fighters that won the war are now left to run it. Boring. This is averted the second time around, where Simon chooses to become a wanderer rather than take a leading position in the government.
Done subtly in One Piece, in regards to the world's greatest swordsman, Dracule Mihawk. While what he was like when he was younger is a mystery, as an adult he seems to have no secondary goals, and has become bored with nothing to accomplish, and jaded because so few people can give him a challenge. As a result, he tries to pass the time by doing things such as wiping out Don Krieg's fleet and chasing the survivors halfway across the world (though only because they disturbed his nap). Which seems to do nothing at all to alleviate his boredom. When he meets the main crew's swordsman Zoro, who's aiming for his title, he's impressed by the younger man's determination and encourages him to surpass him.
This is also why Gold Roger turned himself in to the World Government in the first place. He had seen everything, done everything, and had nothing left to do. Seeing as he was dying from an incurable disease anyway, he figured he would turn himself in and do one final thing: tell everyone, right before they executed him, that he had hidden all his wealth somewhere, and that whoever claimed it would be rich beyond their wildest dreams - so long as they could find it. And so it began...
At the very beginning of Black Cat, when the mob accountant they have captured asks the duo if they would do him a favor and let him see his family once more, Train immediately says OK, because catching and taking him right to the cops would be too boring.
Spoofed hard in Slayers. One episode features a treacherous prince who plots to murder his older brother in order to become first in line to the throne. Lina asks him what he plans to do once he is king. The prince is absolutely dumbfounded by the question, and awkwardly says that "Ummm...I was kind of planning to rule and stuff...I guess."
Lupin III's cop, Zenigata, actually manages to capture Lupin. Inevitably, Zenigata begins to realize that without Lupin to chase around, his life is empty and boring, as Lupin was the only criminal that truly challenged him. In one story, Lupin sits in jail for an entire year awaiting his execution. Zenigata spends the year getting more and more depressed and dreading the execution day even more than Lupin. When Lupin escapes at the last minute, Zenigata is overjoyed, and the chase resumes.
Part of the premise of One Punch Man. The hero, Saitama, has grown so strong that he can take any opponent out in one punch. However, this strength has made him completely apathetic, always disappointed when the next big challenge ends up going down the same way.
In addition to Volkner, the Pokémon anime also had the Orange Islands champion Drake. He was wondering how long it would be before a challenger would defeat him when Ash made his way there.
Alucard from Hellsings main motivation is trying to find a human that can kill him because he's bored of being practically agod to the point of agreeing to reducing his power level to make fighting more of a challenge.
In Transformers Armada Megatron was able to kill Optimus, but afterwards it had left empty and bored with his Arch-Nemesis gone, and spent the next few episodes doing nothing. When Optimus is resurrected, he is back to his old self again.
Cunningham from IGPX. He and Team Velshtein achieved the championship quick, and at a younger age than any previous team. As it turns out, this got boring quick for Cunningham, who desired a real challenge for the title. Enter Takashi and Team Satomi...
In Saki Shinohayu Dawn Of Age, Kanna was undefeated at games, and as a result, got bored with winning all the time. She then got into mahjong, and while she did fairly well at first, she then lost to Hayari Mizuhara. Judging from herreactionwhen she lost, though, perhaps she was happier when she was undefeated.
Bleach: In his backstory, Baraggan Louisenbairn conquered Hueco Mundo to become its God-King, but eventually became so bored that he was about to have his own army fight each other to the death before Aizen, Gin, and Tousen showed up to usurp his rule.
The Joker has often said that he doesn't want to kill Batman, because if he did then it would spoil all their lovely fun.
But in Emperor Joker, it's revealed that he literally cannot imagine a world without Batman... no matter how hard he tries, despite having gained cosmic power and ruler of reality.
In the Going Sane storyline, Joker actually regains his sanity and settles down to live a normal life when he thinks he's killed Batman; after he's beaten Batman there's no point in being the Joker any more.
There is evidence that Batman himself could succumb to this if he would ever "win" his war on crime. He's somewhat uninterested in actually keeping villains put away, when someone with his intelligence and vast fiscal resources probably could, simply preferring to let others (who really suck at it) do that for him. Them breaking out defines his purpose and justifies putting on the cape and cowl every night (which is why he has been accused of being as insane as the people he fights).
Other stories posit the opposite. He nearly went into a Heroic BSOD in one story when the Joker broke out of Arkham three hours after Batman captured him, and the Joker left a message taunting Batman about it. Batman's greatest dream is a Gotham that doesn't need a Batman.
In the Emperor Doom Graphic Novel, Doctor Doom succeeds in conquering the world by brainwashing everyone. By and large he's a fairly benevolent monarch and does much to solve many of the world's problems. He makes the world a utopia but in order to maintain it he has to attend all the boring meetings and make all the decisions. Unfortunately, he's bored out of his mind, such that when the one unaffected hero manages to break the spell on a few others, he lets the rebellion win. He'd rather be a conqueror than a Desk Jockey.
In the Marvel: The End series, Thanos succeeds in acquiring the Heart of the Universe and defeats the entire Celestial Order (Galactus, Infinity, Eternity, Order, Choas etc.) and finally ends all existence in the universe other than himself, but finds his efforts to be utterly pointless. He then discovers that a power other than them may have even being manipulating these events to the point that Thanos himself will realise this, so using the Heart of the Universe, Thanos restores the Universe to the way it was before.
In CrossGen's Mystic, the villainous Magus succeeds in casting an immensely powerful spell that turns all his citizens into mindlessly obedient undead master soldiers. With no rebellions or riots to quash, he becomes comically bored.
The 'Crime Syndicate' of DC Comics has become the defacto rulers of their own Earth. It's so boring they start their own rebellions against themselves just for the fun of smashing them down. 'Thankfully', the Qwardians get their mad on and decided to kill everything and everyone.
In a DuckTales comic, Flintheart Glomgold once manages to take over Duckburg while Scrooge is away fighting Magica DeSpell. When Scrooge returns, he sends Glomgold through a Paranoia Gambit that eventually results in him giving up his ownership of the city so that he can start anew.
Another comic (but not DuckTales) has Magica venting over her inability to steal Scrooge's Number One Dime. When her familiar asks if she really needed Scrooge's dime for her Midas Touch amulet, Magica realizes that no, she doesn't. She still has the other dime Scrooge gave her in her first appearance, when she was collecting the dimes touched by the world's richest. (She originally wanted Scrooge's Number One for extra power.) Making the amulet, Magica gains the Midas Touch and becomes supremely wealthy - but is still upset because she never did beat Scrooge. Even flaunting her new fortune doesn't work, as Scrooge is just happy to know she won't bother him anymore. When she destroys his money bin by turning it to gold (making it too soft to contain his cash), he logically decides to sell the gold to pay for a new one, and then some. This is the last straw, and Magica destroys her amulet before Scrooge could do just that.
A few Alternate History stories have Avengers villain Kang The Conqueror actually succeed in his quest to take over the Twenty(first) Century. He quickly finds that administration is not his forte.
Which isn't too far from what actually happens in the storyline it's making a parody of.
In a Tear Jerker issue, Superman competes against someone who has similar powers and and whose method of rejuvenating himself would eventually kill him. Because of a technicality (the rejuvenation process is considered cheating), Superman wins. Superman then reveals that he's learned his opponent was The Last of His Kind and sorrowfully asks "when you're Superman, what's one more victory?"
A pre-Crisis story had an old pre-WW2 supervillain (despite the fact that this was Earth-1, where Supes himself was supposed to be the first superhuman) give up his life of crime to go star-hopping with his "alien friends". He comes back to Earth to see home again while he can, but is a bit peeved that his tales of travelling in space are disbelieved and that he's mostly been forgotten in favour of Superman, so he gets his friends to rejuvenate him temporarily so that he can have one last splash of super-villainy. He fights Superman, who lets him win so that he can die in triumph.
In the Archie ComicsSonic the Hedgehog there is a dimension where Knuckles the Echidna went mad with power and, in an attempt to "bring order to chaos" as he phrased it, he began to conquer the entire planet. He vanquished all enemies, hero (Sonic, Shadow, Tails, etc.) and villain (Eggman, Ixis Naugus, Snively) alike, making sure to take their souls to form the core of his army for extra insurance. However, upon ruling it, he became extremely bored, and allowed a few Freedom Fighters to exist - despite knowing their location already - so as to keep himself entertained. Eventually, dark Knuckles, better known as Enerjak, decided to look for other worlds to conquer three decades after this all had transpired, and in turn sealed his fate.
A similar thing occurred after the first Robotnik was finally defeated. Mobius is free, Mobotropolis is reclaimed, everyone is happy...except Sonic, who's completely overwhelmed by the tense political climate, the overwhelming hatred of the Robians, and of course, the lack of a single enemy to fight. He goes so far as to wish Robotnik was back, so he'd know what he was fighting. Fortunately, Naugus showed up soon after, followed by the second Robotnik.
The reason why Dr. Eggman, than Robo-Robotnik, decided to invade Mobius Prime. He succeeded to conquer his own Mobius, wiping out the Freedom Fighters in a massive nuclear attack in the progress, but without any worthy enemy to fight, he got bored with his victory and so started the Second Robotnik War in Mobius Prime in order to "fill the void".
Light: This was all fun and games, but even I was growing tired at how easy it was to have the great detective L in the palm of my hand. Seeing him powerless to stop me was a thrill; but like all thrills, it was losing its edge. Even having his name, the name I wanted so badly to know—was all nothing now that I knew it. I felt like it was game over. It was the same thing as beating the final boss in a video game and seeing the end cut scenes. It was not satisfying once the task was actually completed. Was the hunt truly over? I wanted to win, but did it have to be so quickly? I was hoping to play a tad longer.
Voldemort: This is what I envisioned, but not what I truly wanted. I feel as if I am a child on Christmas morning. All of the presents have been opened and now I feel only disappointment that the excitement is over and done. Don't you see Lucius, for one such as I, it is not the crown or the glory of victory, but the blood and the battle. I am not like you, I cannot find satisfaction in being king.
Subverted in the Animaniacs/Lion King fanfic The Tiger Prince. Once Pinky and the Brain take over the grasslands, the Brain happily immerses himself in the minutiae and paperwork of government (and does a fine job of it), while Pinky, of course, can amuse himself for hours with a ball of lint.
Films — Animated
Megamind. Once the title character defeats the hero, he doesn't know what to do next. The first thing he can think of is get in a relationship with Roxanne.
Films — Live-Action
In Superman II, there's a scene showing the complete boredom of the three Kryptonian supervillains after they conquer the world. (And before Lex Luthor arrives to get things moving again).
In Maverick, after Bret and his dad have successfully pulled off their scheme and are now living the pampered high life, Bret intentionally leaves a large portion of the money they won in a position to be stolen by Annabelle Bransford. When asked why, his response is "Because it's going to be a whole lot of fun getting it back!"
In the film version of Camelot, the idea that evil people will never be satisfied, even in victory, is spelled out to Mordred by Arthur.
"I'm like a dog chasing cars. I wouldn't know what to do with one if I caught it."
Also his revelation why he doesn't want to kill Batman.
"I don't want to kill you. What would I do without you? Go back to ripping off mob-leaders? No, no. You... you complete me."
This all comes back in The Dark Knight Rises. With the Joker defeated and new laws in place shutting down nearly all organized crime, plus with Gordon running a cleaner, more efficient police force there's simply no reason for Bruce Wayne to don the Batman suit. However, he's unable to readjust to normal society and becomes an antisocial shut-in. This comes back to bite him hard when Bane arrives... while at one point Batman would have been able to fight him off, years of inaction have dulled his senses enough for Bane to physically dominate him.
In Mystery Men, Captain Amazing is bored because he has managed to put away every supervillain in Champion City, leaving only thugs. His solution is to use his influence to get his arch-nemesis Casanova Frankenstein out of the mental asylum. It doesn't end well for him. It is left somewhat vague just how much it is this and how much it is a desire to keep his sponsorship money (his agent suggests that Amazing's fights being boring to the public is at least a partial reason for him losing sponsors), but given that the scene that culminates in him coming up with the solution starts off with him ranting about the bad quality of the fight, it is at least partly this.
Mr. Nick of The Imaginarium of Doctor Parnassus has always known this, which is why he usually tends to give the doctor another chance, so that they can resume their perpetual game. Parnassus himself is genuinely suprised to discover this, considering he always believed that Nick simply enjoyed watching him suffer by winning.
In Rocky Balboa, Dixon agrees to fight the aging Rocky because no current boxer can touch him. The fans also seem to agree with this trope. Dixon dominates his opponents so easily he's become a boring Invincible Hero, and people are quickly losing interest in watching him.
Inigo Montoya of The Princess Bride, after defeating the Six Fingered Man: "Is very strange. I have been in the revenge business so long, now that it's over, I don't know what to do with the rest of my life." Luckily, Wesley wants to return to a "normal" life with Buttercup.
Wesley: Have you every considered piracy? You'd make a wonderful Dread Pirate Roberts!
"My work here is done. I'm needed elsewhere now. I'm needed wherever outlaws rule the West, wherever innocent women and children are afraid to walk the streets, wherever a man cannot live in simple dignity, wherever a people cry out for justice."
"All right, you caught me. To speak the plain truth it's getting pretty darn dull around here."
In Die Hard, Hans Gruber quotes the line about Alexander after taking over the Nakatomi building, implying that was his favourite part of the plan.
Conan the Barbarian experiences this after becoming King of Aquilonia. He eventually leaves for high adventure on the Western Sea.
The movie did a brief variation of this, where his band of thieves' successes had left them worn out and complacent.
Similarly, this is the impetus for the Discworld book The Last Hero: Cohen the Barbarian is bored stiff as the Emperor of the Agatean Empire. He decides that being Emperor is no fun...but more than that, neither is getting old, or living past the age of barbarian hero. He and his Silver Horde (of seven other veteran barbarian warriors, all septegenerians at the youngest) go out to destroy the gods for allowing this to happen.
There's also references to a Discworld parallel of Alexander, named Carelinus, who apparently conquered the entire world, save for Fourecks and the Counterweight Continent (Fantasy Counterpart Cultures of Australia and China respectively). Cohen observes that it's no wonder, since one's all dried up, and you can't get a decent beer in the other. The minstrel they've captured (long story) tells Cohen the line "and Carelinus wept, for there were no more worlds to conquer." He explains that seeing Cohen looking down at the Disc ("bin there... bin there too... bin there twice, I think... bin everywhere I can see") reminds him of this. Cohen appreciates the comparison: "Yeah, maybe a bit like him. 'cept without the sissy crying, of course..." At another point, it's inverted to reflect the actual quote (see Real Life below)—that some scholar told Carelinus that every star out there might be another world, and he cried because he realized he couldn't conquer them all in one lifetime. That becomes Cohen's real grievance—that there's so much to do no one, no matter how dedicated, could get it all done in one life.
The Worm Ouroboros: The protagonists win, but find nothing else interesting for them to do after their victory. They wish for the conflict to happen all over again, causing the entire thing to start over again. This is the purpose of the title, as the Ouroboros is a symbol of a snake or dragon eating its own tail, symbolizing cyclicality.
Hero's version: about midway through The Chronicles of Amber, Corwin starts realizing that he doesn't have any real interest in holding the throne, and that superficial ambition and spite towards one of his brothers was the only reason he was trying to claim it in the first place. Even before someone else is picked to be King, he announces his intention to abdicate.
Ulysses in the Alfred, Lord Tennyson poem has this attitude.
In A Song of Ice and Fire, King Robert suffered badly from this. A conquering king who saw the girl he fought the war for die and was forced into a loveless political marriage afterward, he's grown fat and keeps talking to his old friend Ned of abandoning the throne and becoming a sellsword. The only joy he seems to find is in the occasional tournament... though it's soon pointed out to him that no one in their right mind is going to strike the king in a melee.
In The Lord of the Rings, after they manage to destroy the one ring, the epilogue is all nostalgic about adventure and about never being able to do anything greater than the greatest deed ever done...
This would have been shown in an unfinished sequel The New Shadow, which as a result a cult forms that worships a dark evil.
In The Divine Comedy, Dante encounters the ghost of Ulysses (Odysseus). Ulysses explains that he died after leaving Ithaca and sailing out into the Atlantic Ocean *after* the whole taking-twenty-years-to-make-it-home-from-the-last-adventure thing. Yeah, it was just too boring being king of a great land and having a queen who adores you.
Ithaca in real life was thought to be a small island kingdom with a few shepherds and a small city (there are about a dozen places claiming to be Ithaca, all pretty similar). You really can see the crafty genius of the Trojan war getting bored from that.
Time Scout: Skeeter's life post Heel-Face Turn is rather disappointing. It comes to a head: You just beat up a knife-wielding thug and handed him to the cops! You just carried the woman he was beating to the hospital, receiving warm congratulations! You just handed a truant kid over to the cops and felt a connection with a formerly antagonistic cop! You just got to stand up to a bigot! You ... just got fired. Now what?
Taken to the extreme in one of The Lost Books of the Odyssey. Achilles abandons the Trojan War on Odysseus' suggestion and goes to faraway lands, and defeats the strongest warriors here and there until there is no doubt that he is the strongest man in the entire world. Then, desperate to be rid of him, an emperor gives him the key to heaven, where Achilles ascends, killing demigods and demons until he finally kills God himself — and is left, sitting on God's throne, wishing he had never been born.
Played straight in the Humanx Commonwealth Flinx books, in which the protagonist's last words, having saved the galaxy from inexorable doom after spending years scouring it for a solution, are: "I'm bored".
At the end of the Codex Alera series, the First Lord Octavian a.k.a. Tavi implies this, as the normal day-to-day task of running Alera seems a bit boring compared to the wars that have just concluded.
In Sonic the Hedgehog in the Fourth Dimension Sonic manages to go back in time to prevent the accident that transformed the friendly Dr Kintobor into the evil Dr Robotnik. All of his animal friends don't treat him like a hero, because he never became a hero, and the only practical use of his abilities is searching for that final damned chaos emerald; neither of which our hero is enjoying.
The adversarial relationship between Dr. Cox and his boss Dr. Kelso is established very quickly in season 1. So you'd think that when Cox winds up destroying everyone's fear of Kelso, (which makes even Ted, a combination of Butt Monkey and The Eeyore willing to stand up to Kelso) and leaves Kelso a broken man, Cox would be rejoicing. Instead he complains that the game is no fun unless Kelso is playing it too and quickly irritates and humiliates Kelso into returning to form.
That's how JD and Elliot's relationships work. As JD himself said, when he got something, he doesn't want it anymore. This changes by Season 8.
On 30 Rock, Jack Donaghy finds himself working for a Brand X version of Comcast which doesn't do anything but take in money from its affiliates; he is informed it's the "perfect business" since they can essentially just sit back and let the money make itself. A natural innovator, he is aghast and quotes the "Alexander" line at the top of the page, attributing it to Die Hard. He's also depressed in the final season when he successfully completes the goal he's been working towards the entire series, and becomes a CEO. The final episode has him quitting NBC and going back to GE, allowing him to work his way back up.
An evil bastard CEO also quotes the Alexander line when he finds himself bored with his success. He ends up making a Deal with the Devil to go back in time to when he was a young man so that he can have the fun of re-conquering the world. (Hilariously, he has to pay the devil in cash because the devil already has his soul.) This being The Twilight Zone, things don't end well for him.
Rod Serling: Some people should quit when they're ahead.
In another episode of the series a deceased crook having been mistakenly sent to heaven soon becomes bored and restless from getting everything just handed to him, feeling that he is getting everything too easily for him to really appreciate it, so much so he asks to go to "the other place." Of course, he's already there.
This happens in the first episode of Leverage as the team makes a multi-million dollar payout and are all mentioning how they could retire. Instead they continue working together using their skills for good.
Sherlock ends up having this in the conflict between Jim Moriarty and Sherlock Holmes. In "The Reichenbach Fall", when it looks like he's defeated Sherlock, Moriarty starts whining about how he doesn't have any challenges any more, and has to go back to "playing with the ordinary people." He solves the problem by shooting himself in the head.
Although it's not exactly the same as "victory" would really be getting home, Star Trek: Voyager sort of had this trope in the episode "Night". After having four years of endless attacks, death and mayhem you think that travelling through an area where they're more or less safe might be better. But even Janeway says "Strange as it sounds, I almost long for the days when we were under constant attack. No time to stop and think about how we got stranded in the Delta quadrant."
The evil law firm Wolfram & Hart from Angel takes the trope to heart. "We're not interested in anything as prosaic as winning". They just want to throw evil spanners in the works.
This trope is the focus of the Breaking Bad episode "Gliding Over All": Everybody who could pose a threat to Walt is now dead, Walt now has more money than he could possibly hope to spend or even launder and thanks to his new deal with Lydia, Walt's "empire" has basically become an average 9 to 5 job.
In Once Upon a Time, it's shown in "Welcome to Storybrooke" that when Regina "won" by casting the curse, she took a day to really relish it. But she quickly realizes that the town that the curse created is so unchanging that it's the next best thing to a "Groundhog Day" Loop. It takes her three days to get bored.
Case in point,
Dr. Hopper: Beautiful day, isn't it?
Regina: (Grinning) Yes... Yes, it is.
Dr. Hopper: Beautiful day, isn't it?
Regina: Save it.
Urquhart spends the second and third seasons of House of Cards (UK) constantly feeling the need to stir up trouble just so he can have something to do.
Discussed in a NoReservations episode where Anthony and a chef discusses the success of another chef who's signature dish was sauted Brussels sprouts. The chef in question had to take it off the menu because he lamented "I'd be in the damn Brussels sprouts business."
The main characters from David Bowie's "Running Gun Blues" and "Saviour Machine". Both are intended to bring peace (the former a soldier, the latter a machine designed to stop war, hunger, disease, etc.), but once their objectives are met, they eventually become bored and partake in the destruction they were meant to stop.
"I've got what I wanted, now I don't want anything, I got what I wanted and now my life is just boring"
Probably the most ancient example: Beowulf as an old king rides out against a dragon, even knowing he can't survive. Forget the motive given to him by the 3D movie - in the original Anglo-Saxon poem it is simply the desire to die fighting.
There's a bit of logic here: according to Norse beliefs, if you died of old age, you'd be denied entrance to Valhalla, in which only heroes who die in battle are welcome.
A lot of ancient Greek heroes seem to have this. Most of the time, it translates into hubris. Bellerophon, for example, wasn't satisfied with getting everything he wanted, defeating every monster he fought, and being hero-worshipped and having a freakin' flying horse. Nope. He decided he wanted to be a god. That didn't end well for him.
With others, like Achilles, it's not so much Victory is Boring as Having the Perfect Life is Boring. They could refrain from heroics or fighting and be the happiest man in the world, but it would mean that their name would not go down in history. And Greek heroes would rather die than let that happen.
Then there's Zeus, king of the gods himself. He has to resort to trickery to get his sister Hera to marry him; then after their wedding, he quickly tires of her nagging dislike of him and goes out to trick a gazillion mortal girls into sleeping with him.
In The Epic of Gilgamesh, the mighty King Gilgamesh has beaten all his city's enemies, harvested the forest of Lebanon and built invincible walls. He's so bored the gods create a wild man to be a challenge for him.
Dilbert: Dogbert once conquered the world in minutes using Mind Control. He didn't actually do much with his power other than force people to hold signs praising him while wearing brassieres. In the end, he told everyone he was retiring to go sit on a soft pillow.
Dogbert: No matter what I do, it always feels better when I stop doing it.
The Dalek comes to this realization in the Doctor Who audio drama "Jubilee".
Video games in general. Once you've won the game and done every quest, the time has come to move on to the next game. Basking in your victory gets boring quickly.
Which is why MMO's with their own game universes that never end are so attractive. A well crafted MMO will only get boring when the player's imagination finally runs dry. In fact, just about any game which allows player enough control to do something not intended by creators can qualify.
Cody in Final Fight saved Metro City, got the mayor's daughter and is the baddest street fighter in all of Metro City. What does he do? Start picking fights until he gets thrown in jail. He escapes from jail just in time for Street Fighter Alpha. To quote the guy: "I saved the city, saved the girl, but couldn't save myself..."
In Final Fight Streetwise, it gets worse - he's so addicted to battle that he lets Belger's younger brother Father Bella turn him into a horrid monster just to keep raising the ante. He and Father Bella are the final Dual Boss.
In Mortal Kombat Armageddon, Shao Kahn's ending reveals him to have finally achieved his goal of conquering all the realms... and going insane with boredom as a result.
The flash game Mastermind World Conqueror, in which you control a Diabolical Mastermind trying to conquer to world, ends like this. He destroys the planet (same as conquering, he looked it up), and escapes in a one-man shuttle with nothing to do but gloat and reflect. "I guess I didn't think this through". Still, he decides that it's totally worth it just to flip off the floating debris that was once Earth and the worst thing to him was the fact that he didn't bring any cheese snacks.
The sequel to the first Ratchet & Clank game starts out this way; the titular heroes have saved the world and been through the cycle of praise and fame, and now they've got nothing to do. Fortunately, it is the start of a sequel...They get significantly better about their downtime later in their careers.
In World of Warcraft, Maiev Shadowsong has spent most of the last 10 000 years either acting as IllidanStormrage's jailor or chasing him. When she finally defeats him with the aid of the players, Illidan says that "The Huntress is nothing without the hunt." Maiev regretfully agrees.
The train of logic behind Lord Dominion's actions in Freedom Force. He's already conquered every other dimension, and rather than just steamroll over the Insignificant Little Blue Planet, he decides to give evil humans Energy X and let them tear the planet apart for his own amusement.
The eighth gym leader in Pokémon Diamond and Pearl, Volkner, has an apathetic attitude to you challenging him because he's won every challenge he's every had. You snap him out of it when you beat him and he breaks into laughter.
Red from Pokémon Gold and Silver may be in this state. What was he actually doing at Mt. Silver in the first place? Probably, after he destroyed Team Rocket, defeated Blue, become the Pokémon Champion and caught ''Mewtwo'', he just had nothing to do. Normal life just didn't satisfy him anymore, so he just left the outside world, living secretly at Mt. Silver without anybody (well, except probably the people at local Pokémon Center) knowing... Until Gold/Kris/Lyra came and defeated him. Where did he go then? He's never referenced in any of the other Pokémon games (reasonable since Gen III because he had his own journey back then and he was at Mt. Silver during Gen IV), not even in Gen V (except for his cameo in Pokémon Black 2 and White 2, where he competes in the World Champion Tournament). Where did he go after that? Maybe he saw himself as a kid in you... and started his great journey all over again... just like Ash Ketchum, but with a 3-year-break.
Sonic the Hedgehog is prone to this. For instance, in Sonic Adventure, he plans to take another vacation after his quest ends and ends up running off at the end of the game.
This is averted in the new inFAMOUS2 game, where they designed it to were the players can make their own levels for others to play. Making the missions never end.
Conquer the world in Civilization, decide to continue the game... and realize that with all the enemies defeated, there is actually very little to do anymore.
For many players, the boredom can set in as soon as you have established a clearly dominant position in the game. This is why later installments no longer require exterminating all opponents to win, but rather by attaining world domination by owning a certain percentage of the world's territory. Civ III required 66%; Civ IV required about 50%, but it could fluctuate a little.
This is YoshihiroShimazu's entire reason for joining the 'losing' side in every Warriors game he's in. He finds being on the side of the stronger guy and having victory be all but assured boring, and would rather go against long odds. Especially prominent in Warriors Orochi 3 where he defects from Orochi's army by basically invoking the trope on the spot.
Rival Schools' ending for Hyo Imawano, the main boss of the game - he wins and has everyone under mind control but realizes that no one loves him.
In the first Persona game, this is what the Big Bad Kandori feels by the time you reach him. After basically achieving godhood, he discovers having no one to oppose is him makes any further effort on his part rather meaningless, which makes him severely depressed. He steps up to fight after being insulted by Nanjo.
Disgaea 3: Absence of Justice gives us a truly twisted take in its Big Bad; Super Hero Aurum, after defeating Mao's father, the Overlord, became depressed that there were no more villains to fight. To fix that, he becomes Geoffry the butler and raises Mao to be the strongest Overlord.
'Dwarf Fortress' is sometimes considered boring once a stable fortress has been developed, as there is almost nothing short of the Hidden Fun Stuff and Megabeasts that can pose a threat to the strongest of forts.
Midway through Final Fantasy VI, Kefka succeeds in murdering Emperor Gestahl, draining the power of the Warring Triad, and effectively becoming a god, and the source of magic. However, upon obtaining such power, he discovers that there's nothing meaningful to do with it. One year later, this line of thinking has fueled his rapid descent into nihilism.
Exaggerated to ridiculous extremes in the remake of Alfredo remake from Action 52 Owns. The final boss is actually the character from the original game who hijacked the remake and attempts to prevent it from being made, explaining that the end of a game is a Fate Worse than Death for a video game character. It turns out he's right, too. Once you beat the game you become trapped on a blank screen with no escape and nothing to do.
Mad Scientist Klaus Wulfenbach of Girl Genius suffers from the inversion of this: he took over most of Europe by sheer necessity, in order to stop what was basically a continent-wide war, and he successfully imposed peace. But he hates it, not because victory is boring, but because it's anything but. Being the dictator of an empire, he's constantly forced to deal with politics, tasks of state, petty rebellions, etc., whereas he would much rather be left alone in his lab to pursue his research.
This is the reason for the main arc's launch in Kid Radd—the player of the main character's game has beaten it and put it to rest.
The Platypus Comix story "Raiders of the Lost Arc" has a reincarnated Joan of Arc fight Osama bin Laden in the Middle East. After she defeats him, all the terrorists of the world surrender, which in turn leads to the disbandment of the US Army. The comic ends with Joan apparently unable to find anything to do with her free time other than mundane chores.
Mulberry helps a robot run for President of the United States in one of her comics. After he wins, she cheers, then nonchalantly gets up and walks away, giving one of her friends a turn at the robot's controls.
xkcd has this happening to Google in this strip, when they realize that they don't have anything evil they can do, since they already have everyone's information
In his 100th episode, the AVGN came to the realization that his purpose as The Nerd is meaningless without bad video games. At the beginning, he was wishing that his game room wouldn't be cluttered with so many bad games. But when ROB the Robot removed them from existence (for its own purpose), that victory felt hollow.
This meta video about the Demoman from Team Fortress 2 being a character in a fantasy game ends with the character winning and the narration going as such :
CONGRATULATIONS. YOU KILLED ALL THE BAD GUYS. NOW YOU HAVE TO GET A REAL JOB
Cue Demoman crying over having to work as a cook.
This is partially why Gavin Free tends to mess up a lot in Achievement Hunter's Let's Play videos. He feels that if he wins too much, the videos become boring. An egregious example was one episode of the group's Let's Play Grand Theft Auto IV series where he purposefully made Team Lads lose to Team Gents several times in Cops n' Crooks because the Lads were winning too often. Lads' leader Michael Jones was not pleased with this revelation and temporarily threw Gavin off of Team Lads until he was officially reinstated after winning Lava Wall in Let's Play Minecraft.
Pinky and the Brain: The Brain once succeeded in taking over the world by building a full-size replica of the Earth out of papier-mache and luring the population there with free T-shirts. Unfortunately, that left him as the ruler of an empty planet. A comet then destroys the real Earth, leaving Brain and Pinky stranded in the fake Earth, where their plans start anew (much to Brain's relief, one may imagine).
In another example, as an accidental result of a time-travel scheme, in the present day all the citizens are replaced with Pinky-like morons. This technically means the Brain has won, since he can easily rule the world with citizens like that. But Brain is horrified, since as he explains to Pinky, while this makes it easy to rule the world, who would want to? He immediately goes back in time to try to change things back.
Mojo Jojo from the Powerpuff Girls in the 10th anniversary special Powerpuff Girls Rule actually managed to achieve victory after getting the Key of the World (you read right). But get this, rather than rule with evil intent he makes it a better place much to the surprise of his long-standing nemeses. However as he thought over his achievement he realizes it too boring and promptly goes back to his usual villainy.
This is the entire gag in the Huntsman segment of Freakazoid!. Crime always seems to be in a lull, so Hunstman finds out that being a superhero is boring when there's nothing around to beat up. Instead he does mundane things with his time like visit his brother or go to the aquarium. Extra comedic effect when contrasted with the intro to the segment, which is much more action-packed (and longer) than the actual segment itself.
In the episode "Hereafter", Vandal Savage (an immortal, fast-healing, superintelligent human conquerer and former caveman) is enduring the solitude and loneliness of having destroyed humanity in stoic fashion when Superman is transported forward in time by Toyman. Upon Superman's arrival he receives his former enemy with friendship and sends Superman back into the past to stop him, having decided that his former plans for domination were meaningless.
In "A Better World", the Justice Lords are rather bored, sitting in the watchtower, since they have conquered the world, and the best crime they have to fight is the occasional college protest. You can even see how eager Martian Manhunter was when he heard of a storm and questioned if they needed assistance in evacuating, only to quickly become depressed when it was stated the area was already evacuated. It is actually because of this that the Justice Lords decided to invade the Justice League Universe to help "fix" it.
In Recess, after the gang retakes the fort they built from Lawson, they realize that the struggle was much more fun than just hanging around, so they dare him and his friends to try and take it back.
In the Adventures of Sonic the Hedgehog episode 'The Last Resort', Robotnik claims to have retired, and Sonic slowly goes crazy from the lack of evil plots to foil.
In the Batman: The Animated Series episode "The Man Who Killed Batman", Joker is clearly unconvinced of his nemesis' demise and goes about robbing a diamond store to force Batman to come thwart him. After a standoff several hours long, he grudgingly admits his greatest foe is gone and that crime is no more funwithout him. He orders his gang to take nothing and leaves empty handed.
In the Teen Titans Go! episode "Super Robin", Robin gains a bunch of superpowers and solves all the world's problems in three seconds. With no crime to fight, the Teen Titans disbands because they no longer have a purpose.
In the Axe Cop episode "No More Bad Guys", Axe Cop is bored because he has killed every bad guy on Earth. In the end he wishes for every alien in the universe to be evil just so he'll have something to fight again.
The thesis of this book is that this trope is why large states eventually collapse.
Milton's quote at the top of the page is a misquote. The original quote is actually a subversion; Alexander is said to have wept because, as he put it, "So many worlds and I have not conquered one." He was crying because he knew he'd never have enough victories. (A scene in Reign The Conqueror show this eloquently, when one of Alexander's generals is disturbed by how how tiny Macedonia is compared to the rest of the world map Alexander has, and how small the territory they've conquered thus far is relative to the rest of the world.)
Michael Jordan arguably got bored of winning so much he quit basketball to play baseball (there were many other reasons, of course.) However, the challenge of a comeback to win more titles rejuvenated his drive to play.
A rather acidic Take That from Augustus: when informed that Alexander had wept upon having no more worlds to conquer, he remarked "I am surprised that the great general did not realize that keeping an empire is a far harder task than winning one." Augustus went on to live the aversion to the hilt, taking great pleasure in his rule and never tiring of running the Roman Empire.
After finally becoming a superstar from the hit single "Hey Joe", Jimi Hendrix soon got sick and tired of playing the song everywhere he went because the fans demanded it. There's a famous television appearance where he starts playing the song, but then stops calling it rubbish and starts playing a Cream song instead. His time on stage got cut short.
Winston Churchill to his doctor, years after the end of World War II "Don't you sometimes feel lost without a war?"