So the scene went like this:
-coworker: you talked about D&D once, but what is it like?
-me: well, that's not easy to explain...
-coworker: why don't we try it sometimes?
-me: well, games can be a bit long, and I will need to prepare something, and we also need to ready characters before, but I can prepare some for you.
-me one week later: I think I got it in my mind and we could try a short game
-coworker: mh, I don't think I'll be in.
>_>