1: For me, it was personal names with too many of the letter "q", "z", or "x". With apostrophes. Big indicator of "call a rabbit a smeerp"; and generally, a given name turns up on page 1... 2: Large scale conspiracies over large time scales that remain secret and don't fall apart. (This is not *explicitly* limited to SF, but appears more often in branded-cyberpunk than one would hope for a subgenre borne out of Bruce Sterling being politically realistic in a zine.) Pretty much *any* form of large-scale space travel. Low earth orbit, not so much; but, human beings in tin cans going to other planets within the solar system is an expensive multi-year endevour that is unlikely to be done on a more regular basis than people went back and forth between Europe and the americas prior to steam ships. Forget about interstellar travel. Any variation on the old chestnut of "robots/ais can't be emotional/creative". On the one hand, this is realistic because human beings have a tendency for othering other races with beliefs and assumptions that don't hold up to any kind of scrutiny (see, for instance, the relatively common belief in pre-1850 US that black people literally couldn't feel pain). On the other hand, we're nowhere near AGI right now and it's already obvious to everyone with even limited experience that AI can be creative (nothing is more creative than a PRNG) and emotional (since emotions are the least complex and most mechanical part of human experience and thus are easy to simulate). Extra bonus hate for robots who are clearly emotional and creative but insist that they aren't. Designated villans. (Again, not strictly limited to SF, but something that breaks science fiction a lot more than other genres -- it's not entirely unreasonable for a fantasy novel to contain EVIL as a literally-and-materially-existing force in the universe. And, I've seen it ruin a lot of otherwise good stuff: I had a hard time getting through John Shirley's A Song Called Youth because, up until quite close to the end, the neo-nazi antagonists were just Evil People Doing Evil Things even when it contradicted their ideology, before we finally got a good look into the mechanics of control and the details of the ideology that made their behavior make a little more sense.) Another thing that's prevented me from reading SF recently, that might not be as much an attribute of the medium as an attribute of recent trends in SF publishing, is pointless/masturbatory digressions. (I like Neal Stephenson's digressions because they're entertaining. I'm not talking about that kind of digression.) I found that I was unable to finish The Unincorporated Man because of a number of things that I can only associate with unprofessional habits/lack of skill, and the most egregious was the fixation on extraneous details that fail to flesh out the world and appear to be interesting only to the author (for instance, there are a couple pages about how the protagonist -- ostensibly an old man with his youth recently artificially returned but characterized like a fifteen year old boy -- decides to name his computer Sebastian). To a lesser extent I saw these tendencies in Daemon, even though that book is generally more competently written. Presumably this is related to these books gaining their popularity prior to going through an established publisher, who would have an interest in cutting out masturbatory passages like this before printing. 3: 1 megaJoule of thrust Should be meganewton, no? However, I admire your restraint in discussing the snake oil that goes under the name of 3He. For me, it's long been a red flag that things, whether fictional or ostensibly serious, have gotten into "walk away from this" territory. 4: How about manually-aimed guns? Self-guided bullets exist in the lab and will be standard sniper issue within a decade. You can currently buy rifles with with technology reminiscent of a CounterStrike aimbot (it was too easy to detect cheaters whose reticules would lock onto the enemy's head; much harder to detect one which automatically pulled the trigger at the exact moment your wavering aim happened to coincide with the enemy). And that's just current-gen tech; we could hypothesise a pistol with waterjet-based attitude & inclination control, twisting in your grip to point at the naughty heat signatures in front of you. And yet, so many SF characters are only as good as their own aim when they try to have a shootout... (I apologise in advance for potentially derailing this thread onto one of the strange attractors! I can repost this in 100 comments' time if you prefer.) 5: Faceless 80's style corporations ruling entire planets (hint: who handles the externalities?) Wasn't part of the point with these that the companies would just ignore them and let the externalities exist and make things terrible for the workers, until they packed up and left when it got too much, all as a sign of their callousness? I mean it was always a very thin cover to criticize global capital doing that. For me it is aliens in almost any context. Very rare are the examples of the times where they are portrayed in a truly alien way. Far too often they are somewhere between "gross oversimplification of a society, racism-lite", and even more often it is scientific racism of the 20s gussied to slide under the radar (like what The Iron Dream was calling out and most unfortunately, ignored). And that's because they are meant to be that. Niven and Pournell get a lot of praise of the Moties that I've never quite understood, because the society doesn't make sense and what they wrote weren't aliens, they were a reskinned setup of their fears to criticize second wave feminism. Ringo, same, it is just a mob so he can glory in slaughter of the political groups he hates. Even with nice aliens like E.T. they are just McGuffins to trigger growth rather than an agent with their own agenda. Never mind how all these run headlong into the apes/angels problem. So yeah, aliens. I think Peter Watts is the only one I've read who does aliens really well, because he set out to make them alien instead of a stand in for something else. 6: 1. Ignorance of the fact that FTL travel always implies time travel. Only very interesting human stories can allow me to gloss over that. The Expanse series is my guilty pleasure in that regard. Still they could just prevent the original plot by talking to their past selves with the time machine that they have on board. I think you mentioned something similar while discussing Iron Sunrise. 2. "Let me fix that impossible problem with my space wrench" aka "the inverted tachyon reflector beam closes the catastrophic singularity". Once an author resorts to that resolution, I have to close the book. 3. Not limited to SciFi: Women suddenly lose all competence when a man is around. That's a subset of your "out-of-character" trope. 4. Not limited to SciFi: Otherwise intelligent character suddenly sabotages himself or everybody else so the story has a reason to go on. Even worse is the trope of "let me keep this vital information a secret for no reason other than that it will create an excuse for drama" and finally the worst offender: 5. Characters being prodigies in 15 scientific fields at once aka "the author is too much in love with their hero" problem. So the master assassin is also a competent computer scientist, chemist, sniper, electrical engineer, race driver and can impersonate accents in 10 languages? This is expanded into the SciFi problem where a colony of 5 people maintain a nuclear reactor, but not as a stupid appliance that they operate like a microwave, no, one of them repairs the machine that took hundreds of professions to come together to make in an afternoon with a wrench.... I struggle to give this one an easy name, but basically it's about any story that ignores that it takes a planet-wide network of industry to make anything technologically advanced in today's age. In my previous job I was asked why we didn't manufacture the mainboards for our appliances in Germany and the answer is: "because there is nobody here who CAN". What makes some authors think that a space station will have someone on hand who can even read the structural specs for the material your antimatter generator is made out of let alone manufacture anything? Unfortunately the above has made it completely impossible for me to enjoy Star Trek since my late twenties. :( Thanks for letting me rant here though :) 7: you are not going to get dust or gravel pinging off the hull ... unless you're insanely unlucky But...but what if you're going through a ring system? You know some of those asteroids in ESB were potatoes, and at least one shoe. Seriously now, John Ohno and Mister_DK have brought up some of the reasons I can't stand MilSF (along with what you've said wrt the physics), that the enemies generally stand in for racist/political tropes. Admittedly, I haven't read much of it, mostly seen movies and TV shows, where they always call the alien invaders something like Snakes or Bugs, which seem to be obvious racist epithet replacements.