I consider "realism" in fiction to be quite possibly the single worst plague on the genre in its entire history.
Let me back up a step. We should first define what "realism" is. Merriam Webster defines realism, in relevant portion, as:
3 : the theory or practice of fidelity in art and literature to nature or to real life and to accurate representation without idealization
This means that to be "realistic", a piece of fiction should attempt to cleave as close to what is actually physically possible as can be attained. I should mention at the outset here that there are some instances where realism is not an inherent bad. Certain books and short stories would be irrevocably damaged by the inclusion of the fantastic and unattainable. Crime dramas leap to mind (with few exceptions), as well as fictionalizations of actual events, and various other subgenres that require as much verisimilitude as possible as to not become totally ridiculous in the telling.
The genres I'm specifically referring to here are my primary three, Science Fiction, Fantasy, and Horror. Putting aside that those aren't really three distinct genres for the moment, these are the popular conceptions of these ideas, and these are what I'm primarily concerned with. So we'll leave aside the hard boiled detective novels, the slice of life stories, period dramas, and the like. We are concerned not with life as it is, but life as it never could be.
When it comes to Scifi/Fantasy/Horror, heretofore shortened to SFFH, making the story "realistic" is the single worst thing that you can do to your story, and one of the biggest disservices you can perpetrate upon your readers. I feel like I'm using too much flowery language, here. I'm not John C. Wright, so let's up the vulgarity a bit.
To put it frankly, this shit sucks. Quoting Bradford C. Walker, "The first duty of fiction is to entertain." While realism in, say, a period drama, can be very entertaining and leave plenty of easter eggs for the reader to find, as well as showing the amount of work put into researching the time period being written about, realism in SFFH is nothing short of entertainment killer.
There are exceptions, as there are with every rule, but the majority of the time this is the stone-cold truth. And I hadn't thought of this before I saw that definition while writing this post, but this actually turns out to be very important: In realistic fiction, "idealization" is a sin.
To run with the trend of defining our terms, Merriam Webster defines "idealize" as
a : to give an ideal form or value to
b : to attribute ideal characteristics to
We're more concerned with definition b here, but I trust you get the idea.
The reason that realism fails in SFFH is that we are inherently dealing with things outside of the bounds of the average experience. Your average person will never have to deal with the wilds of Hyborea in Robert E. Howard's Conan tales, or the dangerous aliens in Jack Vance's Planet of Adventure, or simply a box opened on a subway that causes an entire family to starve themselves to death leaving the father destitute and searching for what he can never find a la Jack Ketchum's The Box.
When you come to something that bills itself as science fiction, or fantasy, or horror, or any combination of the three, you're expecting a tale that will take you out of your normal, everyday experience. Something that will transport you to other worlds, or give you a new outlook on our own world.
In short, something wondrous.
And realism, by and large (remember that we're dealing with general terms, here. Your personal example of "wondrous and realistic fiction" does not translate beyond itself), does not allow for the wondrous. It must be firmly grounded in workaday reality, and as this is something that we all are familiar with, we are all able to recognize when something takes us out of that arena. Realism is centered, by nature, in the mundane.
This is by no account what SFFH should be. Arguments can be made that horror, in part if not in whole, can make the mundane horrendous, and I'm not discounting that. But monster tales, supernatural horror, cosmic horror, and subgenres like them, all bring that element of wonder to the table. That sense of something being off. Presenting to us something outside the normal human experience.
Which is, in my incredibly arrogant opinion, what these subgenres are about.
As stated before, fiction should be entertaining. Mundane life is not. Point blank, the end. Put a period on that. The average person's life is not something that you'd want to read about, because it would be interminable accounts of them waking up, performing their ablutions, going to work, working, going home, relaxing, sleeping, and getting up to do it all over again. We already have to deal with that in our everyday lives. Why, in the name of God and all the angels, would we want to experience that in our fiction?
I'll come out and say it, Escapism is a good thing. Anyone that tells you different is lying to you. They are attempting to demoralize you, to kill your love of the fantastical, to beat you down until you agree with them and get back in line like the little drone they think you should be. That your wanting to escape from your mundane, normal life, even for a couple of hours with a piece of fiction, is bad.
It should be beneath you, because you should aspire to be a sophisticate who takes no pleasure in anything except the ironic, the droll, the sophisticated pleasures of your betters.
I'm reading this biography of Robert E. Howard called Blood and Thunder: The Life & Art of Robert E. Howard (which I highly recommend, by the way, if you're interested in the man's life), and in the introduction Joe R. Lansdale has the absolute unmitigated gall to say, and I quote,
"The twelve year old male was perhaps his most obvious mark, being open to all the repressed desires that Howard displays, but readers of all ages have fallen under his spell."
This might seem innocuous to you, but it lights a fire under the ass of someone like me. This belies an attitude of unvarnished, feigned superiority. An air of "I'm better than you because I don't enjoy what twelve year old boys enjoy." And in the interest of poking into the very base of these suppositions that people like Lansdale obviously hold so close as to throw around in such a cavalier manner, what in the absolute hell, precisely, is wrong with what twelve year old boys enjoy?
I've said it before, and I'll continue pounding this particular drum until the day I die, boys are the lifeblood of any interesting hobby or avenue of culture. If you cannot appeal to boys, you will not appeal to anybody. Except maybe snobs who consider themselves above these "mundane" interests like escapism, heroism, romance, action, adventure, and the like. But, as we've seen with SFFH in the past 40 years, these people are not a viable market.
Intellectual critics are not the audience. This is thrown into stark relief when we view the pages of sites like Rotten Tomatoes in film, Kotaku in video games, the Hugos in literature, and Bleeding Cool in comics. What the critics like turn out to be, barring name-brand recognition and guaranteed audiences like Spiderman or Star wars, abject market failures with the fans. There is a stark difference between what the intelligentsia prefers, and what the average person prefers.
As of this writing, the critic reviews are at 26%, while the audience reviews are at 85%. Doesn't that seem like a huge disparity to you? Like the critics might be out of touch? Like they might be too caught up in pretending to be "intelligent" than having a good time?
Bright is in no wise realistic, but by god if it isn't a fun movie. It appeals to escapism, and strives to be entertaining before all else. In my opinion it accomplishes this goal admirably, but Bright isn't the focus of this screed.
Leaving aside horror for the moment; because the goals of a good piece of horror fiction aren't necessarily to idealize, but to terrify; realism is the death of fantasy and science fiction. Cleaving to what's real, by the very nature of the act, pulls you out of what's ideal, or even not possible but entertaining.
This is part of the problem I have with quote-unquote "hard sci-fi". I've expounded on this in the past but it's worth bringing it up again. Presenting only what technology is possible with humanity's present understanding (barring that one, maybe two, bits of magic, the wondrous, the fantastical, like faster-than-light travel), puts your story in a trap. You're trying so hard to be realistic, when in 40 years we'll discover a way around your fiction, or what you assumed to be true and scientifically accurate will be proven false, and then your tale will be in the precise same bin as John Carter of Mars, wherein Carter gets to Mars by getting shot and wishing really hard.
Not that being in the same bin as Edgar Rice Burroughs is a bad place to be. I'd kill for my fiction to be counted on that level. But anyway.
Imagine what you could do if you weren't constrained by some false sense of needing to be realistic. Imagine the magnificent, marvelous, manifold vistas you could present to the reader. Imagine the pleasure they would take in discovering your new worlds. Imagine the pleasure they would take in being whisked away, if only for an hour, from their average workaday life to your ridiculous world that is completely out of keeping with the mundane.
No matter that, as Damon Knight not-so-famously said, the human race could never produce a man like Conan. No matter that he said that Howard's tales lacked "verisimilitude". No matter that your tales are completely impossible in any rational world.
The important thing is that people read/watch/listen to/etc them and are entertained by them.
Science fiction and fantasy are meant, in my view, to give us idealized persons and societies to aspire to be, not drag us down in the mundane slog of everyday life. Conan is a man every man should want to be. Tall, powerful, combat proficient, the man women want and men want to be. The futuristic societies of science fiction are what we, as a society, should aspire to. Colonizing planets, exploring the universe, discovering faster-than-light travel, and getting down with some hot green chicks along the way.
This is the inherent issue with what most people consider "realistic." To their mind, "realism" means that there are no happy endings, there can be no great heroes (despite the glut of them from actual history), and depressing stories that beat the reader down are the height of literature because they're "realistic."
I posit that escapism is the actual height of literature. That inherently unrealistic stories are, in reality, the best stories ever told. That there is no higher goal in entertainment (meaning writing, cartoons, movies, insert your own medium here) than to be entertaining in and of itself.
Now we can quibble over what's entertaining, and that's inherently subjective. But I think that there is a way to get to the root of what is actually entertaining, and that is what the greatest amount of people enjoy.
Yes, I understand the flaws with this model. Justin Beiber, after all, was insanely popular for a few years there. But I don't think that means we should throw the baby out with the bath water. Conan, to present a counter example, remains insanely popular as Justin Beiber's flame of fame has withered and died. Indeed, it's remained so for almost a century now.
Despite the best efforts of the intelligentsia, being so committed to realism, Conan, Solomon Kane, the tales of H.P. Lovecraft, Tarzan, John Carter of Mars, and countless others have remained popular with the "common folk," the plebs. There is a reason for this, and I think that reason is because they are inherently unrealistic.
They are idealized, in one fashion or another. They give people something to aspire to, something to wish that they were, something to take them out of the crushing, mundane existence of their everyday lives. That's why they've endured, while people like Damon Knight have languished in obscurity, and the current president of SFWA can barely crack the amazon ranks of what relative unknowns nail with nobody propping them up.
Escapism, heroism, romance, action, adventure, and most importantly wonder, work, and woe betide the creator who says they don't. If you want my advice, stop trying to be realistic, and start trying to be wondrous. Your fiction will improve drastically, and will appeal to a much wider audience than that stodgy, old, tired realistic fiction that some will tell you that you should be writing. Trust me, their fingers are so far from the pulse of what people actually crave that they might as well be jammed up their own asses.
People are hungering for honest, earnest, escapist fiction. They want to be entertained, first and foremost, and they always have. If you seek primarily to entertain above all else, you will find people who respond to that. There are so many people who have been driven away from SFFH by realism, and they're just waiting for someone to deliver that dollop of wonderment to them so they can remember why they loved this kind of thing in the first place.
Give them that, and your mission will be fulfilled. Realism is overrated. Take people to fantastic vistas their minds never dreamed could exist. The gratitude of the readers will be worth far more than any awards, accolades, or praise any critic of the intelligentsia could heap upon you.