I'm fascinated by steam engines and with Victorian engineering generally, and as a corollary to that, I'm fascinated by the idea of long-lived technologies.
Dreams of warp drives and hyperspace are just that - dreams.
Daleks scared the hell out of me, to the point where I wouldn't go round to another boy's house because he had Dalek wallpaper in his bedroom.
In some respects, big ideas can be a bit too big for a short story - especially if you've only got a couple of thousand words to play with, and you need room for other stuff, like character, description.
I'm always a little bit cautious around invented terminology because so much science fiction is off-putting to the uninitiated. You open up the first page, and it's full of all these made-up words.
I had - and continued to have - great fun exploring the Revelation Space universe, but it was always clear to me that I wanted to write other kinds of books, even within what might be termed the fairly narrow overlapping genre categories of hard SF and space opera.