For me,  everything I write -- and most of what I read -- comes down to the single question "what if?"   This means a fondness for speculative fiction,  of course,  but the question "what if?" can apply to so many other things.  What if I lived in ancient Rome?  What if I lived in Victorian London?  That single query can lead many places,  into historical references or scholarly essays just as easily as flights of speculative fantasy.