When you self-publish, one of the perks is that you can flaunt the rules set by nearly all of the big New York publishers. Also, one of the reasons that the New York houses look down on self-published authors is because the majority of the writers are sloppy and guess what else? They flaunt the basic rules of grammar.
So, why should we care? As English-speaking Americans, we are rigidly taught and are exposed via TV to proper grammar from early childhood. By the time we reach adulthood our literary preferences dictate the genre of books we buy and read. When we--as readers--are really getting into an exciting plot, it can be a jarring experience for a misplaced comma to blur the meaning. Punctuation was "invented" to make the written word easier to comprehend. I thought it was invented by Shakespeare so the actors would know when to take a breath, but Google says it was an Italian printer. The earliest versions of the Bible, had no punctuation, no capital letters.
When I put one of my novels on Amazon and Kindle, I want it to be as PERFECT as possible. You could call it vanity, but I try to have proper grammar, spelling, punctuation and format, as well as creating a satisfying experience for the reader.
Writing a novel isn't a time to indulge in self-aggrandizement. "Hey, see how great I am. I've written a novel and broken every rule written or unwritten." No, this is a time to showcase your talents and give the paying public the good read they expect when spending their money.
Some of the basic, primary rules of fiction are written, some are unwritten. It's important to give the reader a sense of time and place, use all five--see, hear, feel, smell and taste. Is it summer or winter, is your drink too sweet or bitter? Too hot or too cold? What does fear feel like?
The rule of thumb is your novel should be 60% dialogue and 40% narrative. Don't overdo either one. Don't let one character get on a soapbox and rant for a couple of pages. The rule applying to big, cumbersome words or complicated character names is...anything that stops the reader from flowing through the sentence or paragraph is bad.
So, all you beginners (and even some seasoned writers), please take pride in the work you put on the public venue. It's got your name on it.