What did you expect the beach to be? Covered in tile?
Some of these complaints are more inane than others. I think my snarky comment, while made in jest, brings up a valid point. What did these folks expect when they went to the beach? A beach, one for tourists, is mostly sand. There are rocky beaches but they would have complained about too many rocks, I suspect.
This common sense expectation holds true for many things. In a past blog I discussed being reasonable when it comes to hotel prices. If you walk into the Marriott, you don't expect to get a room for $50. Why? Because it's not that sort of hotel. You should know that going in.
Books, too, hold certain expectations. For instance cozy mysteries aren't going to have excessive amounts of profanity or sex, if any. The actual murder and the sex are all 'off screen' as it were. The heroine may stumble upon the body and see that a knife is sticking out of the corpse's neck, but that's as much as the reader is going to know. You're not going to read about the seeping blood, the maggots, the detailed slice across the guy's neck before the fatal plunge, the neck gristle and muscle showing...too much? Okay, sorry.
Each genre has certain rules to follow for a book to be a success. There are exceptions and you can get away with a few things, in rare cases. (Obviously, you're not gong to see hot, steamy, lusty, busty, throbbing, heaving, bosomy genitalia in YA books. If you're self-publishing this sort of stuff, you might get a visit from the porn police.)
Readers expect certain things from books. In gritty serial killer thrillers, you expect a bit of gore and profanity. You expect to see the blood.
Years ago when I was reading Ludlum's novels, I was amused at the times he used italics for emphasis. In fact, I defy you to find more than ten pages in any Ludlum novel where he doesn't use italics. It's expected. The intensity is such that it almost requires it.
In regards to my books, I warn people that there is going to be profanity (not a lot, but some) and in Beta, there is going to be a sensitive topic discussed. I've also told people that I think I've written it in such a way that people are not going to stop reading because they're disgusted. With this subject matter, when the bad stuff happens, I break a rule and tell you what is happening, rather than show it. However, you will get the idea and be able to move on.
Authors who write series have fans who expect certain aspects of the story each time. J.D. Robb's 'Death' series will have some good humor, steamy sex, and technological standards in the each of the futuristic stories. Rex Stout will have fine meals, beer drinking, and subtle humor in the Nero Wolfe mysteries. Sparkle Abbey's Pampered Pet mysteries will show the constant battle for a gaudy brooch between the main characters.
Fans enjoy and expect these things and as authors we cannot disappoint. When Stout died and the publishing company wanted to continue the stories, they accepted submissions from authors on where future Wolfe mysteries might go. In the end, they settled on Robert Goldsborough because he stayed as true to the character as possible. I think they did right by this. I don't think people would have responded well to Nero Wolfe riding a motorcycle. (This is true, one writer had him doing this.)
What expectations from what authors do you have?