I know, what a snob. It seems strange that I don’t, given that science fiction is probably one of the favorite genres of those in my social group. But I have reasons!
Bad writing. People are quick to make fun of the writing abilities of authors of romance novels like 50 Shades of Gray and Twilight and bodice-rippers. But somehow the same formulaic overuse of adverbs and descriptions of things no one cares about is fine in sci-fi.
Unnecessary terminology. I get it. It’s often set on a different planet, in a different universe, where people look different, etc. But it doesn’t matter. The distracting new terminology is never necessary. Remember Dune? I tried to read that book, and the author made up so many new terms for mundane things that there was a glossary. I wish I were joking. No, somehow it was necessary to call a poisoned needle on a thimble a “gom jabbar”.
Endless descriptions. Again, people make fun of Jane Austen novels for going on and on about curtains or clouds. In sci-fi books, the author should describe the scenes to an illustrator and or leave them mostly to the imagination. Long descriptions + bad writing make it hard for this reader to continue.
Lack of compelling characters. The characters are not written in such a way that we can imagine them well or start to care about their struggles. It’s as if after all the effort spent on making up new terms and describing a different world, the author doesn’t have the energy to describe the main characters or give the reader an idea about their motivations or personalities.
Lack of generality. One oft-cited feature of good literature is that there is a timeless portrait of the human condition. It gives us a way to understand ourselves or others better, or see society more clearly or through a different lens. In contrast, science fiction is more of a “what if”. Because it’s speculation on a “what if” situation by a single author, it doesn’t usually give insight beyond what that one person thinks will happen in the event the setting is real. Which makes it less like literature and more like a conspiracy theory.
In the end, reading sci-fi feels to me like a slog through a technical paper written by a crackpot. Maybe amusing for a page or two, but depressing and unreadable after that.
* Asimov is an exception. His work (I, Robot at least) reads more like moral philosophy edge cases illustrated in allegory and he didn’t do anything too frilly with descriptions and terminology.