Sometimes when I read fiction I get the feeling that the only genre where authors believe in characterisation is drama – stories which hinge entirely on human flaws and interactions. All of the others (romance, humour, sci-fi, fantasy, adventure, mystery, even historical fiction; which really should know better, etc) come across as more interested in black and white good/evil characterisation and things which go BOOM. Flaws never inconvenience characters and all inter-relational problems are caused by someone doing something wrong or evil (or a big misunderstanding that even a toddler could clear up, looking at you romance and comedy) rather than actual human interaction – and the problem only gets worse in fanfiction. Real human interaction is full of minor flaws and arguments wherein no one is the bad/wrong/evil person who needs to be “cured” of their flaws, but no one is truly right either. Humans are social animals. That means we drive each other batshit for no reason and if we aren’t something is really wrong.
1) Not all flaws are created equal. There is an important difference between Learned Flaws, Physical Flaws, and Fundamental Flaws. That might seem fairly inexplicable, but it’s actually quite straightforward: authors typically are aware that characters should have flaws (as this is often toted writing advice) but all too often amateur and not-so-amateur authors think that “have flaws” means “one or two non intrinsic and easily fixed flaws which will never affect the characterisation or plot” and dutifully apply one or two as loosely as children’s stickers and then tick off that box as if the problem has actually been solved. Spoiler alert: it hasn’t. They key problem here is that authors tend to favour physical and learned flaws so that they can be fixed later and their character doesn’t have to be messy and imperfect. This is a problem because a character cannot be 3D or interesting unless they are messy and imperfect. There’s nothing wrong with giving a character learned and/or physical flaws, when portrayed realistically, but they are not as useful to characterisation and plot as fundamental flaws.
Physical Flaws: This category differs from the other two categories as it is to do with a character’s body, rather than their mind/soul/heart/personality/whatever you want to call it. Clumsiness is a physical flaw and the most commonly tacked on flaw in fiction. It’s also a dirty useless cheat because it is always there to “prove” that the character has flaws (no, no they don’t because that’s SINGULAR: one flaw, damn it) and has absolutely no affect on the plot or characterisation. It’s just there to tick a box and look cute. Ultimately, it doesn’t actually count as a flaw. Then there are other physical flaws which (sometimes) turn up in fiction… The character has glasses, OMG, so they’ll get contacts by the end that work just like laser surgery instead of like contacts. The character snores, but no one minds or looses sleep because it’s “cute” (it’s not). The character has, gasp, freckles – but good looking ones. The character is “tall and lanky” and then that turns out to mean “conventionally attractive”. But there are some other physical flaws that get used – like being in a wheelchair or missing a limb until that gets cured (that’s not a character flaw, by the way, that’s the author being an ableist, over-privileged bleep-wad). What I’m saying here is that physical flaws do not actually work for the tick box of “character has flaws” because they have nothing to do with the nature of the character and everything to do with the appearance.
Learned Flaws: This is the category of things like; addictions, sexism, and racism. These are flaws which are not physical, but not inborn either. Typically, these are used to show that a character is either a) not perfect because they have some socially unacceptable view which will be fixed by the end of the story, turning them into a perfect cardboard cut-out, or b) evil. Madness in all most varieties belongs here (as with the exception of those forms of madness which a child is born with – those few caused by chemical imbalance and not psychological damage – which count as disabilities, not flaws). For example: people can be born with an inclination to be more easily affected by alcoholism, but no one is born alcoholic. Sometimes it is too late to change, but it is not naturally unchangeable. A person can be more or less inclined to question the beliefs they are a raised with, but no one is born racist, or sexualist, or sexist, or ableist. In all of these cases the flaw is something negative that a person has integrated into their character over the course of their life, rather than an unchangeable facet of who they were born and will always be. This type of flaw can, if used correctly, flesh out a character significantly, but if it’s only there to be cured or fixed in the end then it is worse than having no flaws whatsoever.
Fundamental Flaws: This is the best type of flaw for a character to have, yet for some reason (probably because it makes right and wrong into a murky grey area and renders characters realistic rather than perfect) most authors seem to shy away from it. When this type of flaw is used it is almost inevitably one of: a) selfishness, which is a ridiculous flaw because no one is selfish all the time and everyone is selfish sometimes, b) a quick temper, which somehow never seems to get the character into trouble or go off when not justified or useful, or c) being “too kind”, which likewise never has its real life negative effects like being brutally used by everyone around them and basically being little better than a doormat. Fundamental flaws are an intrinsic part of a character’s personality: they do not come from some event or incident in the character’s past (being cynical is often portrayed thus even though it shouldn’t be) and it cannot be changed or fixed. A person may become aware of their flaws and seek to mitigate them, but they cannot be expunged and the moment a person is put under pressure, the minor amount of control they have over their fundamental flaws will be the first thing to go. What’s more, mitigate does not mean change or remove – a person whose chief fundamental flaw is being rude as in short with people may spend their life mentally reminding themselves to not go so fast and be a little less blunt, but they won’t always manage and when they get stressed they will stop checking themselves for rudeness. Rudeness, inability to admit to being wrong, nitpicking, refusal to stop helping when asked because “helping!”, inclination to assume the worst of people, generalising when specificity is called for, these and so many more are the type of fundamental – inborn – flaws which actually make characters 3D and INTERESTING.
2) Normal people have dozens of minor and major flaws. In fiction dozens of flaws may well be too many to show without making a completely unlikable character, but that still doesn’t mean that the opposite – none to two and tacked on false flaws at that – is appropriate either. If you’re writing a novel length work and are dealing with a main character, you have enough room for about ten flaws – which is both a good number for simulating the dozens that real people have and comfortably shown, provided that you don’t try to have a character arc or “fix-it” moment for each (or any) of them. It also actually works better in a longer piece to have multiple (non-contradictory) character flaws because it means that not every argument or plot problem has to come from one, thus overstrained, issue. Which of the following seems more realistic? Mary; who is “too kind” and has a “short temper” but is never inconvenienced by them and is otherwise completely flawless beyond being slightly clumsy . Or Sue; who is viewed as a miser  because she stopped giving money to charities after scammers took advantage of her kindness one too many times [2&3 due to implicit gullibility as well as being “too kind”], who snaps at people easily and therefore strains her relationships (causing her to be nervous and wary  in social situations and more likely to snap), does her best to keep her pedantic comments to herself at work , who often misses deadlines  because she’s over critical of her work , but who always makes times for her friends (even when she cannot afford to ) and is never outright cruel, despite an unfortunate clumsiness  which puts her in even more awkward social situations? More importantly: who’s more interesting? Who’s memorable? Sue is – because there are ten billion “flawed” heroines like Mary, in all genres, who have that same trio of flaws “too kind”, “short temper”, and “clumsy”.
3) Fundamental Flaws drive characterisation and plot. Here’s another good question: of Mary and Sue, from the above example, which one is it easier to create characterisation and plot for? Plot first. Whenever the author needs a plot device they could have Mary be kind to the wrong person (if they’re willing to let her, gasp, make a mistake) or have a temper tantrum (they’ll never call it that) at the wrong time, resulting in a big fight/misunderstanding with the love interest in order to stretch the plot another three hundred pages, or have her clumsily drop or break something important. But in all of those cases it’s fairly obvious deus ex machina at work and it’s utterly generic. ANY plot can be advanced by shoehorning one of those in. Sue, on the other hand, has more specific plot opportunities, but they’re also more unique and will ring truer than those shoehorned in. If Sue doesn’t like being viewed as a miser she might decide to do something about that or lose out on something because of it (plots!), she might struggle to learn to trust again and stop being gullible (plot!), or start a fight by snapping at the wrong person at the wrong time (plot advancement!). She might be struggling to make a major project by a deadline and may or may not fail to do so if she makes time for her friends when she shouldn’t (plot complications!). Sue’s plots are both more specific and more sensible for her character – they’re harder to slap onto any random character the way Mary’s options are.
So what about characterisation? Well, here’s the thing; plot is best run by characterisation. If you have deep characters you don’t need to further the plot when it stalls by throwing in random fights or EXPLOSIONS. If your plot is running on the power of realistic people you don’t need big misunderstandings to stretch it out or to toss in stray threads to keep interest up. I’ve often heard people say that writing about emotions and interpersonal drama just “isn’t interesting” because it’s “just people sitting around talking”, but the thing is: any well done interpersonal drama can be more riveting than “OMGOSH R they gonna save the world” take 938,934,579,253,283.4. Characterisation is a subtle beast and, when done right, should be infused into everything – the words the character uses, the way they react to people, the way they look (neat, messy, clothing choices, etc, not hair/eye colour or bust-to-waist-ratio!), what they do, how they move, the job they do and hobbies they have, the choices they make, the way the prose describes them, the way other people describe them, EVERYTHING.
The description of Mary shows us that she’s …pretty much identical to thousands of other fictional heroines out there and nothing else, not even an age-range. There is so little characterisation going on there that she’s essentially a list of traits without a character. Then there’s Sue. We know Sue’s an adult (has a job) who often misses her deadlines (so job has deadlines but either they aren’t overly important or Sue is going to be struggling to keep from being fired soon, which narrows down the fields somewhat, plus it’s implied that she has money to spare to be cheated out of and then hoard, so it’s well-paying). Everything we know about Sue points to her being somewhat embittered (viewed as a miser and having lost trust after being too kind and gullible and getting used for her trouble). She’s nervous and short-tempered around people because she’s clumsy and aware of her pedantic , snappish temperament, which tells us that she actually cares quite a bit what people think of her and is likely very sensitive to other people’s opinions. She’s not cruel and she has friends, so she’s not a total social outcast, unless she’s still gullible and those “friends” are just taking advantage of her. If we narrow that down to a briefer description we can say from her flaws that Sue is a generous, kind, distrustful, socially awkward, woman who is reasonably successful in a well-paying profession and probably has an eye for specifics and precision (pedants tend to have this). Furthermore, all of those descriptions bring to mind physical motions (won’t look people in the eye, rushing with stacks of paper, rare but brilliant smiles, cringing at the looks given to her when something pedantic slips out) and tonal clues (“snapped”, obviously, but also “pointed out” and “ostentatiously”) That’s WAY more than we got out of Mary. That’s practically a complete person. That’s interesting.
4) Flaws do not have to be “cured” or “fixed”, damn it. We want people not cardboard cut-outs. Now, one last question: if the author of Sue were to ensure that by the end of her story, all of Sue’s interesting traits – her social awkwardness, her tendency to snap and miss deadlines, her justifiable distrust of people who want things from her, her awkwardness-inducing-clumsiness, her pedantic nature, her overspending on friends, her too strong self-criticism, and all the others – and “fix” them so that they’d all been scrubbed out, would Sue still be interesting? NO. No she would not, because she would be nothing more than a cardboard cut-out of what “flawless” and “perfect” are supposed to be and no longer be a character. Why? Because all of those things were intrinsic to her personality (with the potential exception of the distrust, which is a learned flaw that comes from compensating for her fundamental flaws)! A character arc which focused on her learning to get over that distrust but still staying wise enough to no longer be gullible and easily used would be fine so long as she remained awkward, snappish, pedantic, over-critical and inclined to miss deadlines. Flaws are what make people people. People are interesting. Flat cardboard cut-outs that have “character” written on it are not.