Fiction is a strange beast. Fiction writers make up new worlds (see science fiction and fantasy) or write alternative histories to those produced by our own. (Many a thriller, including Robert Harris’s Fatherland is based on the “what if we’d lost WW2?” theme).
We make up characters and those of us who write fantasy, as I do, bring in magical elements but what do all of these things have in common? There is at least a grain of truth behind each and every one of them. Readers pick up on that.