Backstory, of course, is basically self-explanatory. It's the story that goes in back of the real story. The story before the story. The unseen history that informs all of your characters' decisions and actions. As such, it's understandably vital to the progression and consistency of your tale. It is often regarded as the most fundamental of aspects for a character and perhaps a fictional universe.
One's backstory could be full of tragedy and molded them to who they are now. One could be a simple Origin Story. It could be something triumphant or uplifting like a sports hero rising up or showing how pleasant the maniac used to be. It also could be a total mystery or riddled with different leads that makes the moment when the full backstory is revealed all the more satisfying. Whatever the case, a larger cast theoretically means an infinite number of possible backstories to create a whole fleshed-out cast.
Then, there's this one. In a crowd filled with people who turned tragedy into triumph, went through some exceptional event, or have some abnormal linage, this person is normal. Completely normal. They weren't a go-getter as a child, they just went to school and took everything in stride. They didn't pick up the mysterious MacGuffin that led to many adventures, they put it back down and never cared to think more about it. They don't have a past full of tragedies because they and their folks were smart enough to make sure it never happened. The most you'll get is that they had a loving family with maybe a couple of siblings and relatives and a cool pet. Members of the cast will be surprised to hear, in a world where something extra-ordinary happened to them in the past, only the ordinary happened to this character. This person has what's called a "Surprisingly Normal Backstory".
People with this backstory are won't jump at the call. The Generic Guy, The Nondescript, the Ridiculously Average Guy, and a Vanilla Protagonist may have this kind of backstory. Those who Can't Stay Normal would love to have this happen to them. In cases of a Ragtag Bunch of Misfits, you may have that one member who somehow doesn't display any trauma, drama, and/or alienation that seems mandatory with the membership.
More unusually, villains may occasionally exhibit this trope. Most often this will be to show that they're a Punch-Clock Villain or Obliviously Evil, but sometimes it's to subvert the expectation that every Complete Monster needs a Freudian Excuse; some of them Look Just Like Everyone Else in terms of history as well as appearance.
An important note, because of the work-dependent nature of this trope, the person in question must have their Surprisingly Normal Backstory discussed, conversed, lampshaded, or at the very least be blatantly obvious to count as an example. Slight or borderline "examples" do not count.
- In Fruits Basket, where most characters suffered through bullying, Parental Abuse, and loss, Kagura's main source of pain is guilt over being mean to Kyo as children.
- Naruto: Sakura Haruno. Her teammates have went through some sort of traumatic or extra-ordinary experience note . Meanwhile, the worst Sakura goes through is having other girls tease her for her forehead. She has loving parents and a good home. Plus, unlike ninjas of her generation, she is generic in terms of skill, not excelling in an expertise (Tenten at least mastered ninja tools to make up her also generic backstory), and also didn't inherit a familial trait as her parents are also ordinary. She does admit this in Part 1, which is why she decides to undergo Training from Hell and become a Super Strength-powered medic nin in Part 2.
- One-Punch Man: Other heroes and villains got their abilities from weird and wondrous sources. Saitama, who has the most amazing powers of all, got his powers from "100 push-ups, 100 sit-ups, 100 squats, and a 10-kilometer run, every single day". This is a feat some people can actually do, so it clearly doesn't make sense. Some characters theorize there was another influence at work, and Saitama just doesn't know what it is.
- Pokémon: Ash Ketchum. He's pretty much defined by his relationships with other people and Pokemon. Ash sticks out because, until Sun and Moon, all of his traveling companions were either Gym Leaders or related to Gym Leaders or other prominent trainers. He has a Disappeared Dad, but that's never been expounded upon, and seems to have a great relationship with his mother. Then again, being a Vanilla Protagonist was the original head writer's initial intention.
- Nanoha from Lyrical Nanoha. Considering her Master Swordsmen older siblings, super rich childhood friends, Super Prototype "best friend", Clone Jesus adopted daughter, her other friend who is The Chosen One, and all the other various Living Weapons, Super Soldiers, and Cyborgs she interacts with on a regular basis, the fact that her backstory can be summed up as "youngest daughter of two cafe owners who just happened to be born with a massive potential for magic and her father spent several months in the hospital" comes off as downright mundane by comparison.
- The most famous version of Batgirl, Barbara Gordon, compared to the rest of the Bat-Family. In short, she basically became a superheroine because she wanted to, motivated by wanting to follow in her father and Batman's footsteps. The only interesting part about her backstory is that her father is Commissioner Gordon, whose personal experience with Gotham City's crime has him against her becoming a cop: hence why she's a vigilante instead. Even in continuities where her mother left or she was adopted, it doesn't really affect her eventual decision to fight crime.
- Played for Horror in 8mm: Machine, the Psycho for Hire that slaughtered some poor woman to create a real In-Universe Snuff Film, explains to Tom (The Hero) that he has no Freudian Excuse: "My mother didn't beat me, my father didn't rape me". He is just a sick son-of-a-bitch for the sheer hell of it. The disgust that this speech makes Tom feel is so massive that he pistol-whips Machine to death in response.
- Many of the young mages in the Circle of Magic series had unhappy childhoods before being recruited by their mentors (imprisoned for theft, thought insane and sent to an Orphanage of Fear, orphaned in a shipwreck or plague)— so in the first book of the sequel series it's somewhat of a surprise that Sandry's future student is a relatively well-adjusted son of a police family whose greatest conflict is that he would rather become a dancer than join the police.
- Hermione Granger of Harry Potter has a very simple background compared to other main characters of the series to reflect her Muggle-born status. She grew up with two alive and well-off parents who work as dentists. That's it.
- Ron's isn't much more dramatic—his family are magic, but they're fairly normal by wizard standards, at least if you compare him to Harry or Neville. His main hangups are that they're kind of poor and he has six talented siblings to stand out from.
- In The Heroes of Olympus, Piper's angsty backstory is that her famous father didn't pay enough attention to her, causing her to act out. This is in contrast to the rest of the main characters, all of whom have lived through war or lost loved ones because of their demigod status.
- The opening paragraph of Northanger Abbey points out all the ways that Catherine doesn't match the template for the typical heroine of a (gothic) novel: her father wasn't abusive, her mother didn't die in childbirth, and so on, and she had a completely normal upbringing.
- The Amazing Adventures Of Nate Banks Lampshades this—Ultraviolet's backstory basically comes down to "randomly developed superpowers over the course of her childhood," and she admits that it's neither flashy nor exciting. It might explain why she's not particularly passionate about her heroics, seeing them more like volunteer work.
- Six-Claws from Wings of Fire, in a series where just about everyone has some kind of messed up family life, had perfectly fine parents, and the narration of his short story lampshades this fact. The rest of his backstory described in that book is quite dramatic, though.
- In an episode of Frasier, he confronts a Con Man who stole his identity and expects the guy to spin a sob story about his Freudian Excuse. The guy casually denies it, saying he had a great relationship with his parents — if anything, they spoiled him — and claims he fell into petty crime out of sheer laziness. Frasier is skeptical but we never find out the truth because the guy keeps him talking just long enough to escape.
- Non Player Companions in the Dragon Age series generally come pre-loaded with lots of personal personal trauma and suffering in the backstory, even though some, like Bethany from Dragon Age II, seem to be naturally better at dealing with it than others. Nevertheless, there is one companion who seems to break the mold: Finn from The Witch Hunt DLC is a mage from a noble family and a prime example of the Circle of Magi system working out right, for once. Unlike most mages in the series, he is on good terms with his family (who had to disown him due to the Circle of Magi's rules but are close to him otherwise), content with spending most of his life in the Tower, and only goes adventuring out of personal interest.
- Though Silent Hill is frequently touted to have everyman protagonists, Henry Townshend is the only one to have a truly everyman backstory. He didn't lose his wife, didn't struggle to treat his ailing wife and eventually murder her, didn't have a batshit insane mother and see his father committed suicide, didn't tragically lose his son, and he wasn't born from an accursed woman or treated second class by his family. He's just a photographer who just so happens to rent an apartment connected to Silent Hill.
- Faction leaders in Sid Meier's Alpha Centauri are each provided with a backstory. While not all of them involve a missing father or childhood on the street in a warzone, they do give off the impression that each leader bears a weight of life experience that significantly impacts their worldview. When Alien Crossfire introduced Sinder Roze, the leader of the Data Angels, she was stated to be... a child of affluent, loving upper-middle class parents who became a black-hat hacker out of teenage boredom.
- In Homestuck, of the main human characters John's life was the most normal and angst-free compared to Rose's passive-aggressive issues with her mother, Jade and Jake both living alone on deserted islands, Jane experiencing frequent assassination attempts as a company heiress, Dave being put through Training from Hell by his abusive Bro, and Dirk and Roxy growing up in a post-apocalyptic world.
- In Phineas and Ferb the Movie: Across the 2nd Dimension, 1st Dimension Doofinshmirtz's more evil and more competent 2nd Dimension counterpart reveals that his Freudian Excuse for being an Evil Overlord is...he lost his toy train. Given what regular Doofinshmirtz put up with as a kid, he's naturally very underwhelmed.
- Young Justice: Wally. No evil parents, no dead parents, and he wasn't raised on another planet or under the sea. Granted, purposefully giving himself superpowers with a chemistry set is an impressive feat, but not an especially dramatic one.
- The titular heroine of Miraculous Ladybug: Marinette's parents are both alive, Happily Married and love her deeply and care about her wellbeing, and so far as we know neither of them have any kind of secret legacy of heroism. Compare and contrast with her partner Chat Noir, aka internationally famous teenage fashion model and Lonely Rich Kid with a Missing Mom Adrien Agreste.