themes, motifs ‘n shit: the formula to being literary
Telling a story seems to be more than just stringing together plausible events. To some extent, there are rules. Stories should roughly follow the “standard model” of introduction -> rising action -> climax -> falling action -> conclusion, of course, though many stories muddy that a lot by having several different sections. In that respect, it is like the harmonic structure of a symphony: there are multiple movements, which may release or defer the release of tension, though everyone expects a suitably large climax at the end, and possibly fanfare and a lengthy denouement.
But anyway, there is that, but that is not all. There has to cohesive structure, a reason to the rhyme, some unique qualities that make it stand out. The characters must be compelling, the dialog must be realistic (or at least suitably emotive and explicable), and the story itself should be at least somewhat novel.
But while all this can be found in a non-fiction tale, suitably arranged, there is a lot more freedom in fiction to produce the “accessories” that fashionable novels nowadays have: motifs, themes, easter eggs, and the like. The kind of metadata that Cliffnotes collates for you so that you can get a concentrated just-add-rote-thinking view of the critical aspects of a work so that you can pass tests that are designed to make people think about what they read in a way that pleases literature folk.
Sometimes these are subtle allusions to previous works that the author expects the learned reader to recognize (something like a secret symbol of the literary cabal). In some modernist works those symbols became necessary for assigning the work any real meaning since the work lacks traditional notions of plot, structure, characters. These themes make the work relevant to reality in the sense of providing the writer a means to express reality through abstraction; or to express inexpressible and clumsy emotions under the steel framework of a taut drama or scathing parody. They can also provide be worked backwards to find insight into the mindset of the writer, or the period in general. The story within the story is more interesting than the story itself, especially for dry historical epic myths like most of the Biblical Old Testament.
But this can be applied to more than just literature; when applied to film and the like it allows for visual themes and styles, with an established field of borrowing. Anime has lots of subgenres which have their own brands of motifs. Sometimes these motifs can cause problems, when a story which is otherwise good seems to draw too many motifs from a well-known story as to seem like a pale imitation. On the other hand, novel additions might make fans too uncomfortable if the additions seem to be at odds with everything around it. Sometimes the feeling or mood is more significant than the actual content. Also with film there is more to worry about outside of the story, like visual design and production quality, which can hamper the best intentions.
So in essence, while the goal of writing something that people would read is to write a story which is engaging and has a sense of forward motion to it, urging the reader to turn the pages, most literature includes a quantity of extra features to pad out the critical side of the work, which even to the unlearned enhance the experience after the initial trial. Some works are lauded enough to merit people actually making a living writing about these aspects. And a decent amount of non-mainstream literature derives its value from these things, a case in point being Infinite Jest, a thoroughly monstrous book that contains neither drama nor comedy, and is usually regurgitated by those lacking intestinal fortitude and a firm desire to take a very slow stroll down literature lane, savoring the intents, the wordplay. These are the delicious undertones in an otherwise gigantic bitter pill, where allusions and imaginations and thinking is far more rewarding.