Not So Similar

"Would the two, for his enlightenment, try to ascertain just what they had in common, and why they belonged to the same party? This resulted in much debating, in the formulating of two carefully worded propositions. First, that a Socialist believes in the common ownership and democratic management of the means of producing the necessities of life; and, second, that a Socialist believes that the means by which this is to be brought about is the class-conscious political organization of the wage-earners. Thus far they were as one; but no farther."

- The Jungle

Our hero just recently noticed that the partner she patrols the city with is just like the guy in her lacrosse club. She could even mistake them for being the same guy the way she's never seen them together. They're both big, goofy, listen to the same music and have a wife named Alice. Further observation reveals that she never sees them together because they don't have much in common that isn't superficial. They are both have afros but Bob buys his hair care from grocery store, Steve makes his own. Bob works out at the gym to stay in shape for his job, Steve is a farmer whose job keeps him in shape. Bob is a night owl, Steve goes to bed at sunset and while Bob's likes to poke fun at things Steve is more of a practical joker.

Our hero hunts the tainted cannibals with unrelenting zeal and takes no prisoners. He's come to learn of another hunter who he has much in common with and believes to be a valued ally. They hunt the same prey using the same weapons, they both wear long coats with sunglasses at night and one night they finally met. It also turns out that both are Not So Different from their common enemy either but for different reasons. Our hero has been exposed to the same taint as them. This other guy is more like them in his behavior. Our hero shows no mercy for the enemy only to make sure they harm no innocents. The other guy doesn't believe in innocents and will roast a person just to spite a cannibal. Our hero will draw his prey away from populated areas to minimize casualties and property damage. The other guy is a Destructive Savior on his best day. Our hero believed they were allies fighting for the same cause but it turns out his "ally" sees him as another trophy to be mounted on his wall.

The narrative allows two characters, groups or otherwise to appear to be alike, they may even be able to fill the same niche in a story but then makes it clear what a mistake it would be to call them interchangeable and if given the opportunity will vehemently correct anyone who makes it. Expect one party to begin with "I'm nothing like ___ if brought to their attention.

Common cases include Cloning Blues, Shadow Archetype and Legacy Character. See also, Our Monsters Are Different. Cast Speciation is a sub trope. If the subjects really were interchangeable at one point see Divergent Character Evolution.

Advertising

 * In general, if the isn't claiming the product in question isn't a more affordable version of the competition then they are using this trope, such as when Verizon Wireless, and AT&T, two American phone companies who used to have a friendly relationship, broke away from each other. They both quickly dedicated much of their budgets to letting everyone know why they should never be mistook for the other.
 * Between the 1910s and 20s Coca Cola became well known in several countries and also became frequently imitated. The most humorous duplicates being Sola Cola and Coc Ola. Naturally, many commercials were put out explaining to the consumer why these knockoffs were inferior to the real thing.

Anime and Manga

 * Piccolo and Vegeta from Dragon Ball, two evil aliens who became friends with Goku. Piccolo initially saw Goku as an obstacle to World Domination, Vegeta just had an obsession with becoming the strongest and Goku's existence got in the way. Also, Piccolo's friendship was genuine, even if he hated to admit it. Vegeta didn't bury the hatchet until the entire universe was at stake. Piccolo at one point has to explain Vegeta's own problems to him.
 * Issac McDougal attempts to recruit Solf Kimblee, another State Alchemist who killed his superiors and apparently defected, in the first episode of Fullmetal Alchemist: Brotherhood. However, while both are defectors from the military and use their alchemy to attack opponents from within (freezing and exploding, respectively), McDougal is a Defector From Decadence who wants to save Amestris from the Ancient Conspiracy, while Kimblee is an Ax Crazy Nietzsche Wannabe.
 * In Neon Genesis Evangelion, Rei and Kaoru have an exchange that amounts exactly to him discussing Not So Different and she invoking this.
 * The Transformers Armada Star Scream takes offense when the Autobots try to compare his treachery to Sideway's.

Comics

 * Blade felt he had a lot of similarities with The Punisher but had to question why Frank Castle pursued a seemingly impossible goal while Blade felt his own was much more reasonable(He even succeeded once already). In Frank's answer Blade(and the readers) start to understand just how different they really are.
 * In a meta sense, Marvel gave Blade to a popular Wolverine writer hoping he could duplicate that success. It was made clear that they weren't really that alike.
 * In the various DC-Marvel crossovers, although both universes have a planet Earth which is inhabited by a human species with broadly similar histories up to about the 1960s, it's been shown that they're fundamentally different down to even the background cosmic principles each is based on.
 * Multiple Man has the power to create body doubles of himself and they usually work together, as they always embody a part of his personality. Sometimes an isolated part of himself can end up behaving very differently from the whole however, many of his body doubles have caused trouble he really doesn't approve of.
 * Judge Dredd has the law enforcement collecting the genetic material of their best judges to ensure they can always create great judges to replace them. Though they often get exact genetic copies of outstanding judges, the clones rarely end up like their predecessors. Just because they have the same talent doesn't mean they want to apply it the same way.
 * This is why Blink ends up as leader of the Comicbook/Exiles, because she is the first on the multiverse crossing team to realize the "familiar faces" they encounter may be anything but.

Film

 * Data has to explain why Captain Picard shouldn't expect his clone to be much like him Star Trek Nemesis. As a robot, he is just one of many of his line but he knows just because the rest have the potential to be just like him doesn't mean they are or even will be.
 * All Through The Night criminal Gloves Donahue describes just how wrong Nazi Franz Ebbing is when the latter thinks they have enough in common to work together.
 * In Inception, one of Dom's nightmares takes the form of  Mal in order to guilt trip over his past mistakes. It works at first but Dom overcomes by realizing and pointing just how much its imitation failed to compare to the real thing.

Literature

 * One book in the Chronicles of Narnia introduces us to Kash, who one figure stubbornly insists is another culture's take on Aslan, no matter how many times the fact it isn't is explained to him.
 * Harry Potter starts to find the similarities between him and Voldemort fairly early on; both are dark-haired, relatively popular guys who started out their years without parents and found Hogwarts to be their home. However, each circumstance is marred with differences; Voldemort was conceived through a loveless union. His mother, while sympathetic, still gave her son to an orphanage. Voldemort instigates much of the antagonism against people in his youth. Harry on the other hand, had parents who loved each other and mother was brave enough to sacrifice herself against Voldemort.
 * The Jungle has a passage dedicated to how some view political parties as autonomous machines full of same thinking people and how naive the believe is. It is demonstrated in a heated debate between a mildly anarchist man who views all establishments as oppressive and wasteful, saying organized religion is the wort offender against a fiercely religious man who believes socialism owes its very existence to the teachings of Jesus Christ, who aimed to disrupt the wealthy and raise up the oppressed, so therefore Socialists should be using The Bible to promote themselves.

Live Action TV

 * Teal'C and Ronon Dex filled the same role on two different Stargate shows, the alien ally who had a long, personal history with the enemy and beat people up. A character who was on both shows noticed this and decided they'd work well together. When they met she immediately began to think otherwise.
 * When Angelus from Angel gets "I'm not like you" shouted at him by Faith he admits it to be true but then adds "You will be."
 * In Fringe the original universe olivia can tell that the alternate version of her is not the same olivia. Peter can as well.
 * In the 2000s Battle Star Galactica, all of the Cylons got backup bodies they could jump into when their current one broke down. Some unexpectedly developed their own, very different personalities which created some friction between them.
 * Baron von Richthoven on Black Adder believed that since his and Lord Flashear's careers neatly parallel each other that their values would as well. Since you're on this page, you know he was sadly mistaken.
 * The regeneration gimmick of Doctor Who is mainly used to keep the show going when the actor playing the doctor is no longer available but different actors leaving a different impression on the character was inevitable. Rather than try to hide it, the show embraces it.

Mythology, Religion and Folklore

 * The kings of Assyria told the people of Judah not to be fooled when Hezekiah said God could save them because they had destroyed the gods of everyone else they conquered. Hezekiah told them that they only did that because those gods were only idols made by human hands.

Professional Wrestling

 * To the uniformed, CM Punk and Jeff Hardy's could have been thought to be much alike. Tattooed, skinny(by Wrestler standards) weirdos who both wrestled in ECW. Before their rivalry became serious(before CM cashed money in the bank on Hardy) the two had a civil argument on Raw which ended in Jeff in saying "You know Punk, we're pretty different." As their rivalry became more bitter, these differences became apparent to everyone.
 * Another relating to CM Punk are his protests against WWE management. R-Truth, Christian and Miz all seemed to have similar issues but as it turned out the first two's bigger issue was with the fans and the fact the general managers were ruling on things they wanted, Punk was upset about management not doing enough for fans. Meanwhile Miz was complaining about being overlooked and declaring himself awesome, similar to CM Punk claiming to be under appreciated and the best wrestler in the world. The difference here was that Miz had always been pandered too until his recent losing streak, CM Punk did not have nearly the amount of exposure even when he became a triple crown champion.
 * When Alberto Del Rio debuted everyone assumed he was an Expy of JBL. Christian called him Juan Bradshaw Layfield. They both came to the ring in cars, both were kind of racist and they both hated Rey Mysterio. The first clear difference was that Alberto was a Mexican aristocrat to JBL's "self made man" stock broker. Then we learned that while JBL had a signature bull horn car Del Rio had a different one every week but what really put them apart was that JBL was much more of a dirty coward than Del Rio, who by contrast is more willing to get his own hands dirty as he believes he is destined to win. Their wrestling styles are very different and Del Rio's now known for his Hammy Herald. Nobody's calling him an expy anymore.

Video Games

 * In Fire Emblem: The Path of Radiance the two hateful jerks you employ sort of stick out for bringing down their more optimistic teammates but at least when they're on a mission together they'll finally have someone agreeable to talk to right? Nope, one of them likes the company but not the job, the other loves the job but barely tolerates who he works with.
 * Also, when Petrine suggests she and Soren are the same he's quick to correct her.
 * In order to get Link's trust in The Legend Of Zelda: Ocarina of Time Nabooru states "she's completely different from Ganondorf" even though they are both thieves and she's technically his subject.
 * X's copy in Megaman Zero claims to be a perfect copy. Zero retorts says the copy's strength and wisdom are both lacking in response. Whether or not the player takes his word for it, they can compare the two X's personalities for themselves and in that area they definitely are not alike.

Western Animation

 * In Batman Beyond The new Batman is somewhat annoyed that the old Batman's enemies expect him to be like his predecessor but he often uses this to his advantage.
 * A few Transformers that knew the original Megatron aren't afraid to tell his Beast Wars counterpart that he isn't worthy of the same respect, regardless of sharing the name.