I do quite a bunch of prep for my games, not because I cant wing the action when I need to but honestly, I like doing it! Still, even with hours of prep for a session a good bit of what a GM relates to the players is spur of the moment, pull it out of your backside, fluff.
I've had players though that seem to catch hold of some of this immaterial color and sink their teeth in. Then I am forced to actually provide details, statistics and so on in the middle of the game and its pretty nerve racking. It makes me wonder if you shouldn't just provide every detail to begin with, even if it takes you a month to prepare.
Recently the PCs walked into a hotel lobby and immediately the droid behind the counter took off. (warned to look for them and inform the owner at their appearance)
I described the droid very briefly, something like a tall gangly droid with multiple arms (dusting, sweeping and arranging key cards) balanced on a small quad-wheeled drive platform that whirled when he made a swift exit. One of the players asked what kind of droid was it? I answered just a servant droid, somebody to tend the desk, clean up etc. But what kind, he keeps asking "a protocol type?" Then another guy chimed in and suddenly they were making plans that might well force me to dig this droid out of a book somewhere. Very annoying, it had no part in the story so I never made it up... or so I thought.
Should I have? Before hand I mean?