I have a few:
- Chosen ones, fate, destiny, &c. When you get down to it, a story with these themes is one where a single person or handful of people is ontologically, cosmically better and more important than everyone else. It's eerily similar to that right-wing meme about how "most people are just NPCs" (though I disliked the trope before that meme ever took off).
- Way too much importance being given to bloodlines by the narrative (note, this is different from them being given importance by characters or societies in the story).
- All of the good characters are handsome and beautiful, while all of the evil characters are ugly and disfigured (with the possible exception of a femme fatale or two).
- Races that are inherently, unchangeably evil down to the last individual regardless of upbringing, society, or material circumstances.
Any time it's not super well explained, I just always assume FTL engines are utilizing some method of spacial distortion rather than actually accelerating an object to such speeds. Like I kind of feel like if you plot a course and there's a planet in between you and your target coordinate you'll just most likely go "through" it via kinda going around it through spacial fuckery
Realistically (I know that word means nothing here), if FTL were possible and utilised by a galactic society, it would have to be the type you're talking about.
Space is mostly empty, sure, but there is enough shit out there to be a problem if something hit it at light speed.
Imagine hitting the FTL button, the stars stretch around you, and then you appear at the other end to find a graveyard of spaceships around a dead planet.
Then the emergency lights start up, and then you realise half of your ship has been hit with the astronomical equivalent of buckshot. Your ship passed through screws and bolts; parts of Elon's fucking Testla from five thousand years ago.
Fuck you Elon.
If we can only accelerate mass to relativistic speed by removing the effective mass. To get a Atsterorid up to C it would have to be effectively masless. To make a warp speed projectile would have to involve some crazy math so the tidal forces don't just shear it appart. Like the hyperfast low mass atoms hitting the decelerating atoms at the front of the object.
In enders game the AI would feather the FTL drives so that ships effectively stopped instantly as mass returned regular physics decelerated the object down to speeds available to regular physics. Which is a little handwavy but not actually that bad
Using an slipspace FTL engine to "warp" giant rocks a mile above a city would be a terrifying weapon.
Zero defense. No warning.
If you're warping spacetime that's a shit ton of energy you're manipulating, which has a lot of Implications about how deadly the average person in the setting is, so it's better to just ignore it and continue with your space opera.