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.
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