I think all of us who love history are drawn to certain times and places. Conversely, there are eras and locales that we instinctively shy away from for various reasons. We accumulate facts and details and are knowledgable about arcane bits of information that most people are completely unaware of.
For instance, if you have ever looked at dolls' hands, you may have wondered why they were molded the way they were, with the middle and ring fingers together and slightly curved inward toward the palm, while the index finger and pinkie were apart and mostly straight. Well, Godey's Lady's Book, the most popular magazine in America in the mid-1800's, had voluminous advice on how fashionable women carried themselves, whether seated, standing, or moving, right down to the way they held their hands. This position I've described was how one was supposed to hold one's hands while at rest. Dolls were designed to reflect the height of fashion, including the positioning of their hands and fingers, and that particular model has been in use right up until the present.
How do I know this? I read it in a book. Why do I remember it? Heaven only knows.
I tend to be drawn to times of hardship and rigor. I'm fascinated by historical tragedies of any kind, from the eruption of Mt. Vesuvius to the Pilgrims' first year to the Donner party to the Titanic. I'm currently attracted to stories of America in the 1930s, especially the Dust Bowl and stories about how people made it through the Depression. My fascination with true crime makes this an interesting era for me, what with all the gangsters and Prohibition.
I also feel an affinity with Regency England. I don't know if it's something organic within me, or if it grew from constant exposure, because all the women in my family read Regency romances by the hundreds.
I don't gravitate toward brother-vs.-brother times of strife. I enjoy reading about the Civil War, but I don't enjoy Civil War romances, where the heroine is on one side of the conflict and the hero on the other. Those types of stories never resolve seamlessly for me, because the reconciliation of diametrically opposite beliefs doesn't ring true. Also, I guess it's natural, given how the war ended, but you rarely find stories where the protagonists are both Southern and everything ends well. Those are always tragic stories of loss and retribution.
Some chunks of English history are less interesting to me than others. I'm fascinated by the Tudors, the Victorians, and the Edwardians. I'll read about any era, really, but those are my three favorites.
Another thing that can pull me out of a historical novel is the use of accents. Ah do not lahk zee foreign ax-ahnts written out phonetically. (This is another reason why I don't like Civil War stories; I think it's a bit patronizing for modern white writers to try to approximate what they think slaves might have sounded like.) I guess I want it both ways. I want to know if the characters have accents or particular speech patterns, but I don't want to have to sound them out.
I admire the research that authors put into their writing. I love authors who respect their readers enough to validate their information and create a convincing universe in which their readers can immerse themselves. I remember being in a writing class in college, and one girl had written a historical romance. (Should I say "an" historical romance?) At first the professor seemed inclined to praise the story, but my friend and I began to point out the historical inaccuracies, much to the other girl's dismay. When the professor asked her why she had so many mistakes and anachronisms, she threw up her hands and wailed, "I didn't think anyone would notice!" A lot of my classmates were upset with us for being so mean to someone else (and causing her to get a less-than-wonderful grade), but even then, I took writing very seriously. Readers do not like to be patronized, and it bugged even then that this girl would assume that romance readers would be too stupid to catch her errors.
People who read history, even light historical fiction, take their reading seriously. They know their stuff. They want to be entertained by writers who also know their stuff.