Biggest difference between writing science fiction and historical fiction?

A story's a story, of course -- any good one needs strong characters, structure, dialog, plot, themes, etc. But different types of stories have their own extra requirements. Writing science fiction, the trick is to make it plausible. It has to feel real. Even fantasy -- like GAME OF THRONES or LORD OF THE RINGS -- has to make readers or viewers believe that dragons and hobbits exist and live and breath in a "real" world. You need to establish rules for how the universe works, and they have to be followed consistently. If the phasers and deflector shields of Captain Kirk's starship Enterprise work a certain way in one story, they have to function the same way in every story. If Harry Potter's magic works one way in one book, there better be a good reason if it's different in the next book. With historical fiction, it has to be accurate. Whatever time period or historical place I may write about, I have to get the facts and details right -- because somebody out there knows more than I do about a given time and place. If I'm wrong or I fudge something, some sharp-eyed reader will catch me and call embarrassing attention to my screw-up. And there goes my credibility, and my story.

For instance, I know quite a bit about vintage cars -- I know that Ford's Thunderbird (right) looked almost the same from 1961-63. But there were subtle differences, and I can instantly tell them apart. (In fact, this '62 T-Bird pictured is wearing '63 wheel covers). There was a TV cop series a few years back, based on the career of a real crusading lawman, set in Las Vegas in 1960. Early in the first episode, a few 1962 cars drove by. Most viewers probably wouldn't notice -- but I did. And I thought, "If the producers can't be bothered to get the period cars right, what else are they fudging?" Took me right out of the story, and ruined the show for me (that, plus the fact it wasn't very good). Knowing how much attention to detail matters in historical fiction, I did 6 months of research for GALLOWAY'S GAMBLE before I started to write. I'll share some of what I learned in future blogs. Can you think of shows, movies or books where the lack of attention to detail or consistency bugged you like anachronistic cars bugged me?