One of the challenges you face when you world build outside of reality is the challenge of "how does that work"? Gene Roddenbery famously answered the question "How do the transporters work?" with the answer "Very well, thank you."
As I work on the next project I am trying to sort out how many alien races I want to have, how much of this universe is "Human", and of course, how they're able to transverse space quickly. Already I've started to consult with friends who are learned in "rocket science" as to how well my efforts to explain how FTL technology is going to work and how FTL Communication will be done.
Another aspect of this world is the development of a race entirely of female robots. This creates particular challenge in that I want to avoid the "What's it mean to be human?" characteristic that defined Data on Star Trek: TNG while at the same time not letting the race become regular women who just happen to be robotic. As someone with some training in programming, I am also trying desperately to avoid thinking about how hard some of the specific subroutines and behaviors would be to program.
My current point of consideration and consternation is the simple issue of "Pleasure". Computers don't have fun. Which begs the question "What is fun?" And with it the follow up question "Why do we do fun things?"
Take playing tennis. Winning, for humans, is a pleasurable experience. We like to win. So how do you program a robot to want to win because it is "fun"? For the robot-race, a given robot might have "Winning" as a personal point of pursuit. When given a block of time, and that robot begins to cycle through choices of pursuits, there would be a non-zero chance that she selects "Win a competition" and then seeks out an activity that will qualify to meet that goal.
The entire exercise is forcing a very strong reflection on the actual physiological triggers in the human body to "fun" activities and how to translate them down into computer code.
Or perhaps it's a matter of hand-waving a bit into the story the same answer many of us would given when asked "why is that fun?". That answer being, quite often: "I don't know; it just is."