A few of the Montana Meth Project ads have serious examples of this (i.e. Bathtub, Laundromat, and That Guy).
Anime and Manga
The title of this trope fits Noein perfectly (the series is even subtitled "To Your Other Self"). Karasu, the Future Badass version of the present-day Yuu, is disgusted by his former cowardly self. Yuu, on the other hand, is scared by how intense and cold Karasu is. However, both are able to reconcile their differences when it comes to protecting/rescuing Haruka.
In a Story Arc of the Teen Titans comic, the Titans get dropped ten years in the future, and are more than a little disturbed to find that, in addition to replacing their mentors and becoming Darker and Edgier, their future selves are the dictatorial rulers of half of what used to be the United States. The future Titans are equally disturbed by meeting their "naive" past selves.
Played for all it is worth in a post-Zero Hour issue of DC's Legion of Super-Heroes when the Time Trapper confronted the Legion with just about every possible future and alternate reality version of themselves imaginable. Most of the duplicate Legionnaires get along fine, but others are either villainous, harder and more cynical than their counterparts, or just plain embarrassing.
Subverted in a pre-Zero Hour issue of LSH v.4 (#40, to be specific) wherein the younger "temporal duplicate" of sweet, shy, and very feminine Salu Digby, aka Shrinking Violet, is initially horrified at the sight of her older counterpart, a (very) butch lesbian. Once they get to talking, though, the younger Salu decides that "I guess I do hope I turn out a lot like you, after all."
Similarly, when Iron Man and Doctor Doom were stuck in 2093, they were not at all pleased with their future namesakes. The villainous future Iron Man was just a relative of Tony's, but the future Doom was Doom himself, a century older and much the worse for wear. Doom killed him without hesitation and walked away vowing never to become "that".
Most extreme version of this is done by the author Dan Abnett. And can be summed up as "Future self comes back to kill me" In the Durham Red comic, and also in a special edition of Warhammer Monthly comic, in this case, with the main character of the Malus Darkblade series.
Adam Warlock was captured by his mad future self The Magus; after escaping, he soul-sucked a nearer-future self to make sure The Magus was definitely dead.
A long running story in Black Panther had a sort of subversion and played straight with. The future Black Panther was an intentional throwback homage to a Silver Age characterization by creator Jack Kirby during Panther's original solo series, which was more light adventure, then his at the time serious personality. The problem was that said future Black Panther was at the final stages of a fatal brain aneurysm ailment, losing his mind and Panther at the time himself was just starting to get the same symptoms.
It turns out that Iron Lad of the Young Avengers is actually a teenaged Kang the Conqueror, who ran away from his future self because he didn't want to become a villain. Inverted in that his older self is the more established character, rather than vice versa, and it turns out that all the characters have to let him become evil, to even attempt to change the future would cause irreversible damage to the timestream.
In The Childrens Crusade, Iron Lad is still determined to Screw Destiny on this point, convincing himself that his timeline has been messed with sufficiently that he's not from the same history as his apparent future self. So he's particularly worried when he visits a timeline with a version of his villainous persona who still works with the former Young Avengers.
Darkseid once met his future self. And was disappointed enough to kill him with Omega Beams.
SuperboyPrime met and attacked his future self, because... he didn't like his old face and beard. If he hadn't judged people by their looks, he could have been amazed by the fact that his future self was the Time Trapper.
Impulse is not at all pleased to discover his future self in Dark Tomorrow is a violent, Darker and Edgier hero who is no longer on speaking terms with his then-girlfriend and seems to be more lenient about the Thou Shall Not Kill rule than present-Imp.
Although even evil future versions of Impulse (he's met several) tend to be nicer than the evil versions of his companions.
Though they haven't met, when young Marcus Langston got his hands on a book that contains all stories of everybody in the Universe, he read his own story and was horrified with the revelation that he was going to become a junkie and criminal, so he rewrote it, making himself a superhero and member of Youngblood - Sentinel
In Ed Brubaker's The Authority run, Midnighter is contacted by a future version of Apollo and warned that he has to leave the team or he will kill Jack Hawksmoor, go insane and become the undisputed genocidal ruler of future earth. It turns out to be part of a Evil Plan by Henry Bendix to disband the Authority, but still...
Subverted in Runaways: Most kids would be thrilled to hear that they're destined to lead the Avengers, but Gert calls her future self boring and insists that she'll never become that woman And since she ends up getting killed by a group of kids trying to become the next Pride, she turns out to be right. Victor would be a straightforward example of this trope, except that he's never actually met his villainous future self. Just hearing about him is enough to give the boy nightmares, though.
Back to the time-traveling warlord Kang the Conqueror, for the longest, er, time, he shudders at the thought that he will eventually become the "doddering old scholar" Immortus. In the Avengers Forever limited series, this changes when Immortus is killed and then is brought back as Kang's alternate self and no longer as his future self. Needless to say, Kang is pleased by the turn of events.
And this trope is even played further by the limited series as particular characters aren't too happy with how things will turn out for them, or how they will turn into. Of particular note is Rick Jones, who meets a one-armed future version of him who is bonded with a Captain Marvel he doesn't like too well. Another version of this trope is how the Avengers find out the possible not-so-pleasant aspects of the legacy they will leave for the rest of the galaxy.
Subverted by Franklin Richards in Jonathan Hickman's Fantastic Four - Present Franklin and Future Adult Franklin get along great, happily calling each other Kid Franklin and Mister Franklin. Then again, Franklin has the power of being superhumanly well-adjusted, far more than any kid who's been repeatedly kidnapped, has seen every one of his relatives die at least once, sometimes possesses godlike powers, and was once trapped in hell has any right to be.
Played straight with his sister Valeria in the same story and her very similar adult self.
Played straight in one crossover with the X-Factor, New Mutants and the Fantastic Four where the ghost of the Franklin Richards from Days of Future Past goes on a rampage of Reality Warping.
It is discussed in Peggy Sue fanfic The Second Try. Asuka thinks her younger self would hate her since during her Character Development she forsook all what she had lived for during her childhood and became a very different person who does not mind showing her emotions, letting others close and loves being a wife and a mother. Shinji disagrees, though. But he thinks his younger self would be shocked and surprised at seeing him (since he had became more emotionally stable and less timid).
Though it's never outright addressed in the canon during a real meeting between the two versions, in some Heroes fanfiction, both Peter Petrelli and Claire Bennet are depicted as mildly disturbed and/or fearful of their future selves, especially sometime during Volume 3. Conversely, Gabriel Gray (i.e. Sylar) has calmed considerably by the time the episode Butterfly Effect rolls around, and even has a beloved son.
George Weasley And The Computational Error has a 40-year-old George Weasley who terrifies the 11-year-old versions of himself and Fred, mostly because Old George isn't allowed to say who he is yet and he has the ability to possess his younger counterpart.
The Pony POV SeriesDark World Series has this happen with Twilight when confronted by NightmareEclipse/Paradox, her potential future self and the true Big Bad. She became She Who Fights Monsters by trapping Discord in a "Groundhog Day" Loop to torture him, in the process deleting Dark World and everyone in it enough times to add up to several hundred million years. Twilight quite reasonably shudders the moment she sees her Cutie Mark, as due to Discord showing her his memories, she's seen just what a monster Paradox has become. The following Wham Line really makes the whole thing hit home.
Lost Christmas has Goose and Anthony. Goose thinks Anthony is a nutter because of his powers, but they're really there to make sure Goose (good future) exists and Anthony (bad future) doesn't.
The Lost in Space movie had Doctor Smith who thought he was rather evil until he met himself 20 years in the future as a half-mutated spider bent on destroying all of humanity. His future self is also less than impressed with him: "I never liked me, anyway."
In Zathura, the Astronaut is a helpful if scarily intense young man who turns out to be the older self of one of the main characters, who came back in time to stop himself from wishing his younger brother out of existence and thus being trapped in the game world forever.
Even funnier, Jennifer's future self happens to pass out in shock gasping, "I'm young!"
Old Biff is pretty scary, given that that version of Biff has just as much of a temper as young Biff, with bitterness that's been marinating for decades added in.
Jennifer also has a similar reaction to the sight of her future boyfriend/husband, Marty. Marty himself never sees his future self, but he learns enough in Part III to avert the accident that sent him down that path.
In Click, Adam Sandler's character is disgusted when he sees his future self cold-heartedly dismiss his father (twisting the knife even further, this is the last time he saw his dad, not even being there when he died). He even calls his future self "pathetic".
It seems that it's subverted in Click, since Adam Sandler's character's body goes into "autopilot" in the jumps where he fast-forwards to the future. While his conscious self comes back into his body at short intervals, he becomes horrified at how things turned out while he was "away", and his unconscious body acts mechanically and treats his loved ones callously. It's more of a Future Me-When-Not-Me Scares Me.
Triangle is pretty much made out of this trope. A woman on a boat trapped in a series of time loops becomes convinced that time only loops whenever everyone else on the ship is dead, so to save all her friends she has to kill all her friends. Naturally, Killer Jess comes off as an utter nutball to First-Time Jess, yet it seems like the Sanity Slippage is inevitable...
Serves as the main plot of William Sleator's The Green Futures of Tycho. Tycho finds a Time Machine, doesn't like his future, and tries to fix it by changing the present and the past, only to make it worse. He repeats this until his future self is a tyrant selling out humanity to the aliens and planning some sort of invasion through time. He finally realizes why (the time machine and the power it gives him over events is corrupting him), but not before the tyrant version (who still has the time machine) starts chasing him through history, to prevent him from fucking up the tyrant's plans.
Double-inverted in The Time Traveler's Wife. Henry DeTamble rarely travels forward in time, but he is often zapped into the past randomly and without warning. On one such trip, he meets up with his future wife, then-girlfriend. He begs her to have patience with him, because he remembers how shallow and immature he was as a young man. Seeing how mature future-Henry is, Clare is reassured.
Also played straight: on one of his rare travels forward, Henry speaks with his now 10-year-old daughter (who his wife is pregnant with in the present) and learns that he's already dead in the future.
For a subversion, see The Time Traveler's Wife's entry under Screw Yourself.
Older Than Radio: Ebenezer Scrooge is not so much terrified at the sight of himself in the future, but by the realization that, upon his death, the only emotional reaction to the news will be happiness (with some mockery thrown in).
Doctor Impossible of Soon I Will Be Invincible mentions meeting "the original villain team" The Delinquent Five when they came from the Fifties to seek help from their present selves, assuming they would be wealthy, powerful rulers by now. Dispiritingly, the heroes and governments are still in charge. He notes "Maybe that was the beginning of the end for them."
In Woken Furies, Takeshi Kovacs finds himself up against an illegal copy of himself made when he was a good deal younger. More vicious and less world-weary, 'young' Kovacs is noticeably unimpressed that his future self hasn't made more of his life, like becoming a crime kingpin or suchlike.
Averted in Simon R. Green's "Nightside" books, since even though Suzie Shooter's(a.k.a. Shotgun Suzie, a.k.a. Oh Christ, It's Her, Run) future self has had half her face ripped off by a spiked mace then cauterized with a flamethrower and one arm replaced by a grafted-on gun, nothing scares Suzie Shooter.
Done straight in a case where Taylor must help a man who's being pursued by his apparent past selves, who are disgusted by how his life turned out, and by future selves who either want to ensure he'll become them, or prevent him from doing so. For the past selves, he's this trope; for the future ones, he's its inversion.
Of Two Minds by Carol Matas and Perry Nodelman. It's established from the beginning that the protagonist is a Jerkass, and becoming more so as she exploits her Reality Warping abilities. The Big Bad is another reality warper, with an oddly familiar appearance . . .
In Animorphs number seven, The Stranger, the Ellimist transports the main characters to the future in order to influence their decision on an offer he made them. In the process they meet their current enemy, who's been promoted, and future Rachel, the present version of which is narrating, and she's been infested by a Yeerk. *cue dramatic music*
By the end of the series their enemy does get promoted before being defeated and getting put on trial, but Rachel is killed, rather than infested.
A sci-fi anthology contained a short story with an interesting subversion of this trope. The protagonist lives in a near-future world which experiences time-travelers from farther in the future. The premise is that adults from the future occasionally travel to the in-story present to impart some words of wisdom or practical advice. This is considered a highly desirable occurrence, and children live in anticipation of meeting their future selves. But the main character receives a visit from an alcoholic bum future self who turns out to be the boy's father in disguise, trying to help his son make better choices and become a better person than he ended up being.
Another SF anthology (The Year's Best SF 3) featured "The Nostalginauts" by S. N. Dyer. The story was about two high school outcasts waiting for their graduation. The SF element? Some 20 years in the future someone will invent a way to send a soundless and spectral image of oneself back exactly 25 years, and a trendy use is to go to your 25th high school reunion with pictures of your life's successes and then go back as a group to show them to your past selves at the senior prom. Turns out most of the kids are more horrified by their future baldness, paunches, and obvious plastic surgery than they are excited by their cars and big houses. And then the outcasts get the last laugh when it turns out the geekier of the two INVENTED the time travel technology, and is far richer than any of his former classmates. After all the other images have vanished, the geek sends back not only his image but the images of everyone at the party he's throwing, so they can all have a laugh at the kids who teased him when he was younger.
In Harry Harrison's The Technicolor Time Machine, the protagonist is approached by his future self with an important message. He notices that his future self has a nasty-looking bandage covering his right hand but when he asks his future self what caused the injury his future self just gives him an evil grin and ignores the question. He spends much of the rest of the book frightened about what's going to happen to his hand. Then, near the end of the book, he gets a bad sliver that a field medic has to use a scalpel to extract, and then the medic discovers that she doesn't have band-aids available and tells him she'll need to use gauze. The protagonist realizes that his future self tricked him into thinking he'd be facing a terrible injury and decides to get revenge on himself for being such a bastard by pulling the same deception. When he goes to visit his past self and we hear his internal monologue from the "other side" of the conversation he takes great joy in making his past self squirm. He's fully aware that his vengeance doesn't make logical sense.
Tim Powers' Three Days To Never features a lot of time wonk based on the central MacGuffin, a method of time travel (and Ret Gone) devised by Einstein himself. At one point, the protagonist's future self shows up in 1980s Los Angeles after the protagonist saves his daughter from choking to death in an Italian restaurant; he's pissed that the timeline where the daughter died, he remarried and lived a happy life got erased in favor of a timeline where the daughter lived and grew up to resent him bitterly. He's come back to a) set the timeline right, and b) get his younger self to buy into Microsoft. His younger self has... issues with this plan, to say the least.
In the 9th Betsy the Vampire Queen book, Undead and Unfinished, Betsy & her sister Laura travel 1000 years into the future, where future Betsy is coldly presiding over a frozen post-apocalyptic wasteland. Present Betsy is more pissed off than scared, but the reader learns that Betsy has skinned her husband and literally bound him into The Book of the Dead, which is plenty scary.
The Grandfather was his future self. He was everyone's future self... He was what you swore you'd never become when you were an adventurous youth, and he was always watching, waiting to strike.
Also happens to Fitz in the Eighth Doctor Adventures... well, sort of. He's a clone, and he meets the embittered, decrepit, thousand-year-old original, now known as Father Kreiner, who's spent all that time waiting for the Doctor to come back to him. He's not too happy to find out he's been replaced, and threatens to kill Fitz before deciding he'd rather let him live to find out how untrustworthy the Doctor is.
Skulduggery Pleasant has Darquesse, a mysterious figure who has been seen by many seers to destroy the world, and it turns out she's Valkyrie (or at least Valkyrie's true-name empowered alter-ego).
In one of the Scary Stories to Tell in the Dark, "The Thing", two friends encounter a horrific skeletal figure one night. Frightened out of their wits, they flee to safety. Years later, one of them becomes very sick and dies. In the last days before he died, his friend realized that he looked just like the skeletal horror they met long ago.
Most of the future heroes are pretty scary. The exception is Sylar, who is considerably nicer...and is rather afraid of reverting to his past self (in one future, anyway; in another, he's President, and has just about everybody else's powers, and is about to top even himself by committing super-genocide.
In the "multi-Doctor" episodes of Doctor Who, you often get this friction between regenerations:
In The Three Doctors, the three incarnations of the Doctor don't get on (especially not Three and Two; the First isn't impressed by either, but they appear to respect him).
Not so much in "The Five Doctors", where most of the past Doctors like Five, but Three and Two still bicker.
In the 2007 Children in Need special "Time Crash", the Fifth Doctor is initially weirded out and irritated by the Tenth Doctor, not realising that it's his future self. Eventually, Ten impresses him, at which point Five takes to him. The Tenth squees at his past-self throughout.
The most powerful villain in The Trial of a Time Lord, the Valeyard, was initially interpreted to be a normal Future Evil Self for the Doctor due to some confused dialogue. However it's now generally accepted by fans that he's actually a time-travelling Enemy Without from the future, created from all the potential and actual evil of the Doctor's first twelve incarnations.
Subverted when the first Doctor meets with any of his future incarnations. Despite being the youngest and least experienced of them all, the first Doctor is somehow able to command great respect from his future selves, so much that they accept his leadership and generally follow his orders without issues. Imagine yourself at eighty taking orders from yourself at five!
On the other hand, they have a very good reason to do so. After all, the First Doctor was indeed known as the most emotionally mature of them. Others were just too busy being Crazy Awesome to worry about that.
Used to great effect in the 2010 Christmas Special, a awesome Yet Another Christmas Carol. The Doctor has tried to be The Ghost of Christmas Past, befriending a young Kazran and visiting him every Christmas for years in order to change him from the bitter shell of a man he is in the present. Amy then does her best being Ghost of Christmas Present, but no avail. Kazran, being Genre Savvy, challenges the Doctor to be his Ghost of Christmas Future.
Kazran: Why are you here?
The Doctor: Because I am not finished with you yet. You have seen the past, present. And now you need to see the future.
Kazran: Fine. Do it. Show me. I die cold, alone and afraid. Of course I know, we all do! What difference does showing me make? Do you know why I am going to let all those people die? Not a plan. I don't get anything from it. It just that I don't care! I'm not like you, I don't even want to be like you. I don't and never, ever will care!
The Doctor: And I don't believe that.
Kazran: Then show me the future! Prove me wrong!
The Doctor: I am showing it to you. I am showing it to you right now. [To someone behind Kazran] So what do you think?!
[Kazran turns around and sees his twelve year old self looking back at him, with eleven different types of freak out written on his face]
The Doctor: Is this who you want to become, Kazran?
While human, the Doctor completely forgets who he used to be and who he's supposed to turn into again after his stint as a human is over. When his Motor Mouth accidentally kicks in and starts rambling in Time Lord mode, he's horrified to hear himself talk. Becoming the Doctor again is essentially suicide, which he's fully aware of.
"The Day of the Doctor" has the War Doctor being unnerved that he'll eventually be the Eleventh Doctor.
War Doctor: Am I having a mid-life crisis?
In The Sarah Jane Adventures story "The Mad Woman in the Attic", the titular character is a future version of Rani, who is appalled at the sight of her.
Inverted in Red Dwarf, where in "Timeslides", Lister tries to make his past self super-rich by giving him the idea for a hit invention before the real inventor patents it. His younger self doesn't want to be rich, and says he'd rather be a broke musician. Played straight in the later episode "Out of Time", where the crew meet themselves from fifteen years in the future. The two sets of crew hate each other so much that they end up killing each other (with the "present" set surviving through Temporal Paradox).
And in trying to explain the paradox to the audience, the camera melts, as it can't handle the paradox.
Ugly Betty where Betty sees a vision of her past self. The earlier Betty is horrified by her future counterpart's lack of optimism and the morally questionable things she does since joining MODE.
The Farscape episode "My Three Crichtons" features a variation on this, with hyper-smart, vaguely-reptilian, highly evolved Crichton being sociopathically self-interested in his own survival, rather than the logic he claims to employ to help the rest of the Moya's crew.
Second Rider Yuuto Sakurai has a very uneasy relationship with his Mysterious Watcher future self. The series treats them as separate entities for the most part, referring to the younger by his first name and the older by his surname.
During the episodes leading into the first movie, we have several moments where "Yuuto" yanks Ryotaro away seemingly at random and then drops him back where he came from. Ryotaro is obviously pretty upset, but when confronted Yuuto insists he hasn't done anything. Then it turns out that the version of Yuuto from a few days in the future is the one to blame, and he confronts his slightly-more-past self to explain the situation.
Dean Winchester gets sent into the future in Season 5, and meets his future self. They're more or less alike, except that the future one has finally completelysnapped under the pressure of all the crap that is constantly raining down on Dean, and abandoned all his remaining morals and standards. Seeing as Dean is already a quite pragmatic and cynical person, you can imagine what that looks like. (He meets future-Castiel too, who also scares him, having gone from a guy who wouldn't know a joke if it bit him to a drugged-out sex guru.)
Not forgetting that in that episode, Sam has been possessed by Lucifer for the last 5 years and is orchestrating a full on Zombie Apocalypse.
It is however unclear if this is really future Dean, or merely a concoction created by Zachariah in an attempt to get Dean to do things his way.
In Timeslip, Liz and Simon both meet future counterparts of themselves. Neither of them thinks much of Liz's first counterpart, who has become inhumanly cold-hearted and clinical in the "Ice Box" research center of the far-off year 1990. Liz prefers her "hippie" future self from the alternative "Burn-Up" future of 1999, though she's troubled by her future self's seeming inability to act responsibly. Simon's future counterpart has given up his name in favor of a number, and has become opportunistic and ultra-rational to compete in the emotionless clone-dominated scientific community of the future. Simon, for some reason, likes and respects this future version of himself, until he turns out to be a bit of a tool.
Also, in "Walking Distance," the future (our present) man scares his younger self so much that the boy falls off the merry-go-round and injures his leg. The man immediately walks with a limp from then on.
An episode of Nikita had this happen to Alex when, while under the influence of ibogaine (and in withdrawal from heroin), she hallucinated a version of herself that had beaten Division and taken back control of her father's company Zetrov.
On the Star Trek: The Next Generation episode "Time Squared", Picard encounters a future version of himself who, according to the camera footage from his shuttle, (seemingly) abandoned the Enterprise in its hour of need. The Enterprise was destroyed, leaving Future Picard as the sole survivor. This is hardly the first time Picard's judgment has been questioned; the last thing he wants is living proof that he's a lousy Captain.
Picard: Are you still convinced he's me? Troi: Yes, but you're not convinced. Picard: Not in the slightest. Except for his features, there is nothing about him I find familiar!
On Star Trek: Deep Space Nine ("Children of Time"), Dax's curiosity in some weird space anomaly accidentally caused the Defiant to crash-land on a planet. The descendants of the Defiant crew found a settlement on the planet's surface; hen Jadzia Dax died of old age, her symbiont was passed down to another (male) Trill, Yedrin, granting him the thoughts and memories of the Jadzia host. This gives Jadzia the unique experience (thanks to Timey-Wimey Ball) of confronting her future self and seeing the consequences of her mistake.
In Star Trek: Voyager, as noted by Sf Debris, if you get more than one Janeway in the same room, they will inevitably begin to argue with each other.
The Garfunkel And Oates song "29/31". It follows a woman at the ages of 29 and 31; her 29-year-old self is an idealisticNaïve Everygirl while her 31-year-old self is a cynicalDeadpan Snarker, having realized her life didn't go as well as she expected it to. Her older self (played by Riki) is annoyed by her younger self (played by Kate), while her younger self is horrified by what she has become.
In Silent Hill 2 James stumbles into a room with a man in a chair, staring into a tv that has nothing on it. Upon examination, he looks and sees it's him, brutally murdered.◊ The creators said they put this there to scare players by showing that this could very well happen to James.
Other people on the team, however, have claimed they simply reused James' model for the man in the chair because they were lazy and didn't think anyone would notice.
In Silent Hill 4: The Room Young Walter is terrified when he meets the serial killer he will eventually become.
In Sam & Max: Freelance Police, the duo travel 100 years forward in time to find that Sam is then wheelchair bound and suffers from dementia. Although present Sam is not visibly perturbed, he does remark later: "Good. Just wanted to check my dementia wasn't setting in early."
World of Warcraft has a quest in which you meet Future You (who is wearing the same gear you are, of course). After the success of the battle he tells you to "get better gear," which one could find annoying.
Bizarrely, one of Future You's comments is, "I can't believe I used to wear that."
Future You can say other things as well, like "When you get to the party with the gnome and the furblog, DON'T DRINK THE PUNCH!"
Past You can say stuff like "Ew. Look at your gear. Have you even been raiding?" and parts with you with "Thanks. No offense, but I'm gonna make sure I turn out better than you."
Other random conversations have Future You admit to a drinking problem because of how much a loser they were at your level. Inversely Past You may complain about how bad your gear is still and say they're gonna get drunk.
It is possible to do these two quests immediately back-to-back. WoW characters are vigorously and formidably psychotic.
Another example is the Infinite Dragonflight, who are bronze dragons corrupted by the Old Gods after a Bad Future. Their leader is Murozond AKA Nozdormu, driven insane by being cursed to see the future up to and including his death.
A similar case in the fourth Final Fantasy XI expansion, Wings of the Goddess, in which Lady Lilith is an evil alternate dark future version of Lilisette and her fourth Spitewarden is you, wearing the same gear from the waist up.
Played with in Retro Game Challenge, where a young Shinya Arino is shocked when you go back in time and tell him about the Evil Overlord-lite he grows up to become in your era.
Averted in Jak II: Renegade. Old Samos and Young Samos never stop arguing, and young Jak is one of the few people to get along with older, phlebotinum rebel Jak.
Bayonetta: Cereza, Bayonetta's past self, seems a bit scared of Bayonetta from time to time.
Cereza is oblivious of the fact Bayonetta is her future self though. Not only that, but she also likes Bayonetta, seeing her as a mother figure ("You're the best, mommy!")
In inFamous, just before he dies, the Big Bad Kessler reveals to Cole that he's actually Cole from the future. This shocks Cole, for obvious reasons.
In the first Marvel: Ultimate Alliance game, Doctor Doom—in addition to being being the Big Bad—is also a downloadable character or can be gotten through the Gold Edition (both exclusive to the X-Box 360). If you have the playable Doom in your party when you meet the boss Doom, it's revealed that boss Doom is from the future. As mentioned in the examples in "Comic Books", playable Doom wasn't happy with his future self.
In Spider-Man: Edge of Time, the Big Bad is revealed to be Peter Parker's future self, who has gone insane due to the death of all of his loved ones and the use of an anti-aging drug he used to allow himself to be alive in 2099. He planned on reshaping the universe in his own image in order to fix his past mistakes.
In Tales of Majeyal when playing as a time warden, your psychotic future self shows up to kill you. If he succeeds it also counts as a Grandfather Paradox.
Even Dr. Robotnik/Dr. Eggman gets this in Sonic Generations. Even though the two of them are working together and are collectively the game's Big Bad, Robotnik looks at Eggman's behavior with puzzlement and asks "Wow. Will I really get that crazy?" At the very end of the game when Robotnik learns that Eggman has never defeated Sonic, he gets depressed and decides to go for a teaching degree instead.
In Star Trek Online, a Federation player will confront the Klingon B'Vat during the Star Trek: The Original Series era. He reveals that he met the version of himself from your time frame and is greatly embarrassed by his appearance. He asks you to go kill him, as it would probably be the most honorable thing.
In Superosity, character Boardy (an amnesiac super-being who isn't sure if he's an alien or a robot) has met a future version of himself who is a crazy, obnoxious jerk, and a further future version who is pure unadulterated evil. He was alarmed to find out the first future him is, according to it, from a very near future, and there have been signs recently in the comic that his sense of right and wrong is beginning to slip. These are only a couple of the futures the cast has visited; Boardy always seems to be either evil or dead. He's remarked on how annoying this is.
Subverted in Fans!!, where the present day characters encounter their past selves, and their past selves mistake their present selves' character development as being a Face-Heel Turn. The present characters then wipe the floor with the past characters, taking advantage of everything they've learned.
Narbonic parodies this with Mell's reaction to her future self. She wants to avoid that future happening not to save the world, but because she thinks that her future self looks lame with contacts.
Played with on multiple occasions in TRU Life Adventures. First, upon meeting his alternate older self, Bob's disturbed most by the fact he's bald. Later, even Old Jack gets annoyed by his younger self.
In the fanmade online comic specialThe 10 Doctors, the ninth Doctor at first refuses to believe that Ten is his future self ( "Where's Rose?"), the first Doctor has no respect for any of the others besides the tenth, Three thinks Seven and Two are complete dunces, and nobody likes Six. The first Doctor is from after he left Gallifrey but before the show actually started — not having met his first human companions, he's a little aghast to learn of his future career.
In the Bad Karma arc of Magellan, time-traveling superheroes come back to Magellan Island to stop two supervillains. The first-year cadets are impressed. But these time travelers are some of the main characters, just aged and tempered. Bill is horrified to meet his future self and discover chronic hair loss. Kaycee Jones finds out that her future self went Darth Vader and killed a supervillain, was discharged from the team, went rogue, had half her face burned off in a superbattle, ...
During the 'Surreptitious Machinations' arc of General Protection Fault, Trudy Trueheart encounters her future self - a ruthless empress who rules the world with an iron fist. While she IS scared by what her future shows she is capable of, her first reaction - much to Empress Trudy's annoyance - is to be horrified by how OLD she's gotten.
Trudy: I have to start coloring my hair... and a diet, got to lose weight... plastic surgery... facelift... got to fix THESE...
Empress Trudy: I LOOK MARVELOUS FOR MY AGE, MORON!
Something similar happens in the second future Jade episode of Jackie Chan Adventures with a one-off character; he grows up to be evil, but Jade changes this. In the first future Jade episode, it happened with Jade herself. Both episodes offer a different version of Jade, the first being a badass and the other punished for being too much of a badass.
Taken to extremes in the second Made-for-TV Movie of Danny Phantom, where the eponymous boy travels 10 years into the future and finds himself turned into the biggest and baddest of all Ghosts, who also happens to be a mass-murdering psychopath more than willing to kill his own family in order to preserve his existence.
"Dark Danny" (aka "Dan"), after original Danny's family dies, goes to Vlad, the only one who could understand him. Vlad then separates Ghost Danny from his Human Danny, somehow keeping all the compassion and whatnot in Human Danny. Ghost Danny then rips Ghost Vlad from Human Vlad and combines with him, then kills Human Danny.
Ghost Danny, after combining with Ghost Vlad, looks very much in pain and, according to much of the fandom, was fighting for control of himself; a battle he apparently lost.
In Gargoyles, Demona uses the Phoenix Gate to return to the past, where she tries to convince her younger self to Kill All Humans before the gargoyles are sealed. Young Demona cries "And I do not wish to be you!"
Subverted because young Demona's fear of the humans smashing her clan leads to her organizing the events that lead up to it. You Can't Fight Fate; the basic premise of the Phoenix Gate is that it can't be used to actually change the past. Using it always creates a Stable Time Loop, no matter what. Since the past has already happened, if you use the Phoenix Gate to travel back in time, your trip is part of the past and thus has also already happened.
The Phoenix Gate is generally a fairly useless time travel device for this very reason; attempts to make use of it for these purposes is futile. Ironically, David Xanatos (himself a villain of sorts) manages to hitch a ride along with Demona (and numerous other people) when his wedding party is sent back to the past via the gate; while Demona, who was responsible for the incident, fails to help her past self at all (indeed, dooming herself to her very own destiny - she even admits that she remembers it at the end of the episode), Xanatos sends himself a coin in the future that allows him to jump start his fortune.
A variant is the episode "Future Tense," where Goliath has a horrifying vision of a future dystopic Manhattan about to put under the control of a older, megalomaniacal Lexington. Fortunately, series creator, Greg Weisman, has stated that he is safe from turning into that in the true future, however his clone, Brentwood is liable to go that way instead.
The Teenage Mutant Ninja Turtles are disappointed by elderly selves in an episode of the first animated series.
Of course, the whole reason Old!Dexter is so revered is due to Badass!Dexter having saved the entire world! He lost his muscle-clad Action Hero physique because it wasn't needed anymore in the scientific Utopia he created.
In the fourth season of ReBoot, Enzo (who grew up into the Darker and Edgier Matrix in season 3) has a younger version of himself restored from a backup. At first, Little Enzo looks up to Matrix and wants to be just like him, while Matrix is irritated by Enzo as a reminder of how weak and naive he used to be. As time goes on, Enzo despises Matrix for the bitter and cynical Anti-Hero he's turned into, and Matrix realizes how much he has strayed from his more idealistic youth.
Although it was technically a Mirror Universe, when Coop meets his alternate self in the last episode of Megas XLR, it's still a dimension a decade or two in the future relative to his own — and Coop is a tyrannical (and muscular) despot. However, the regular Coop is unconcerned about turning into him — maybe just a little too much so.
In the Family Guy movie, Stewie Griffin: The Untold Story, Stewie visits his future self and finds that he has become a lame momma's boy.
When Batman and a few Leaguers end up in the future on Justice League, it's discovered that the only thing more brooding and scary than Batman is an aged, cane-wielding, cruel Bruce Wayne. (The same one seen in Batman Beyond, in fact.)
A variation shows up in another episode, after the League meet their Alternate Universe counterparts, the Justice Lords, who took over the world and rule it with an iron fist. They're not the least bit scared — but the rest of their world is terrified when they find out, and the US government starts to take action to destroy their world's version. This ultimately ends as up the focus of Justice League Unlimited's second-season arc.
The South Park episode "My Future Self 'n' Me" is based on this trope. However, it turns out that Stan's loser future self is just an actor paid by Stan's parents to try to convince him not to do drugs.
Ironically, at the end of the episode a REAL future Cartman, who has become so immensely rich he can afford time travel, tells past Cartman that this was the moment he realized that he had to work hard and get healthy to become a success. Past Cartman, thinking its a trap, declares that he's never going to read again and only eat junk food. After a few seconds Future Cartman is morphed into an obese, and apparently very poor, loser.
Subverted in another episode, in that it's not their future selves, but just the sheer amount of phlebotinum involved, they should've just built a time machine.
In an episode of Duckman, Duckman meets his future self, who warns him not to go to his sons' science show, telling him something bad will happen. Then another future version of him appears and tells him something bad will happen if he doesn't go. This happens several times, back and forth, until finally, he's afraid to do anything.
An inversion is done in Static Shock when Static is sent to the future by mistake. After hearing so much about how responsible and powerful his future self is, he begins to feel rather inadequate. Until he manages to save the day and win approval and all.
One episode of the second Teenage Mutant Ninja Turtles series has Donatello be transported to the future, where the Shredder has taken over. It's more "My Future Brothers Scare Me", especially when he sees that Mikey, laid-back and sweet in the present, is a badass with several mechanical limbs.
Averted in Teen Titans, despite a fairly typical Bad Future episode. While all the Titans (except Starfire) have fallen into decay (much to the dismay of their past counterparts when Starfire recounts her solo adventure), Robin is fairly pleased with his future.
Robin: So… "Nightwing", huh?
Beast Boy is pretty upset when he finds out he's going to go bald.
American Dad! had an episode where a cyborg Stan came back from 1000 years in the future to steal Francine from his past self. He first tries to do so by making Stan look like an (even worse) Jerkass, but when Stan realizes what he's doing, Cyborg Stan decides to just plain abduct Francine, and ends up getting thrown into the world's largest hot chocolate, yielding the immortal line "You choc-blocked me!"
The "scares" part comes along when Stan hears his future self talk and realize he's speaking in a strange mix of Mexican and Canadian accents. Future!Stan reveals that Mexico and Canada have annexed the US at some point in the future. Given Stan's "red-blooded American" personality, this probably horrifies him most of all.
In My Little Pony: Friendship Is Magic, Twilight Sparkle encounters a future version of herself with a messy mane, torn unitard, bandanna, eyepatch, and even a scar. The future self has no time to explain the events that caused her to be this way before, so Twilight becomes obsessed with figuring out what's going to happen. Eventually, through a series of unrelated incidents, she resembles the future self and realizes that there's no apocalypse at all. Then she tries to go back in time and tell herself to not worry, but this causes her past self to become obsessed in the first place.
Young Justice Blue Beetle learns from Impulse that he would be the vanguard to the Reach's invasion, where he becomes a super muscular version of Black Beetle.