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.
Honestly this thread went through a lot of ones that I love/hate but one trope I can't get enough of is "the aliens are uncaring" like in Roadside picnic where they show up, throw some trash down on earth, and leave. They are never seen or heard from, they don't even bother with us in the book.
There is another series with a deus ex machina where some AIs evolve into godlike beings and then just mysteriously leave, but I forget the name of that one as well.