Love them or hate them there are a lot of common tropes across the science fiction genre. What are some of your favorite and least favorite tropes?
I think it goes without saying that one of the least favorite tropes is Deux ex Machina. I couldn't quite put my finger on it at first, but after watching the German TV show "Dark" I was utterly dissatisfied with it. The entire series up until the very last episode is about this inescapable time loop and alternative universes which is pretty cool while watching it, but then you get closer and closer to the end wondering how they are going to solve this impossible problem. Then surprise they just do it instantly in the last episode.
Another trope I am not very fond of is nanotechnology where there are trillions of tiny robots that can effectively act as magic. It just feels like a lazy way to write science fiction because you really want a fantasy.
A trope I do actually like despite how overdone it is, is the idea of a precursor or forerunner. It often brings to light the absolutely massive scale of the universe which I find fun to think about.
I can often excuse single-biome planets this way, too. For example, Hoth. Sure, Hoth is an "ice world." But I bet if you were to actually map out Hoth's climate you'd find that it has regions that range from "Antarctic" to "Colder than Hell" to "Holy Shit Steel Shatters Here" and the Rebels just wisely put their base in one of the "Antarctic" regions. Tattooine and Arrakis likely range from "Sahara-like" to "Sandblaster Inferno" and we just see the characters in the "Sahara-like" places.
One of the best subversions of this that comes to mind is an episode of Stargate SG-1 where a couple of characters get shunted to an unknown Stargate that's buried in an ice cave. When one manages to reach the surface to find a howling snowstorm and an ice sheet stretching as far as she can see she reports back that "we're on an ice world, it's uninhabitable, there's no way there's any life here. We're on our own" And then it turned out that they were literally in Antarctica, on Earth, and eventually a rescue helicopter shows up.
What I'd really like to see is a desert planet with a small sea at the pole to provide a habitable biosphere around it, and when we actually see a city down there it looks like a perfectly ordinary green landscape with trees and wheat fields and whatnot. Because on the scale of a planet you can easily have a region the size of Great Britain that's lush and green while still having the world as a whole count as a "desert planet."
I'll just drop this here.
https://www.youtube.com/watch?v=EriZ9ruZq1E