I was once at a panel at an SF convention where the panelists were talking about how to self-edit your work. Looking for bad phrasings, etc., etc.
At the very end, I put up my hand and made the last comment, namely, that they really ought to warn the audience that if they took this advice, it would change the way you read for pleasure, forever. Two panelists nodded. The third laughed and said it would destroy it -- which is a bit strong. Still, once you keep an eye out for passive voice in your own work, you will be in the middle of the fight scene and thinking, "Unnecessary use of the passive voice." It does distract.
I recently read a Celtic fantasy, sort of set in the Dark Ages, and am meditating on the corollary. Namely, if you read (wallow in) enough history to be good at world-building, it will also change the way you read. Forever. Because I remembered enjoying this book more than I do now. And part of that is reading about a Dark Ages masquerade ball.You can get away with that if you go for conscious anachronism, but that has to be a continuous theme, not a one-shot. And you can get away with merging lots of elements from many cultures, provided you heat them hot enough in your imagination so they melt and fuse together into a new alloy. But you had best not do it with 99% from one culture and bits from far-distant lands or eras.
Like a Dark Ages setting except for a masquerade.
And the religion no longer convinced me. People following the Old Religion, Christians -- and you get no pious people thinking that the other side are dangerous maniacs who put the entire kingdom in peril. On both sides. The pagans should be thinking that the maniac Christians are out to offend the gods, and the Christians should be thinking that the pagans are out to offend God by worshiping a demon or a nothing. And both sides think that the divine, if offended, is capable of coming down like a ton of bricks. You find this in both the prophets (where women of Israel tell a prophet that they actually had a better life when they baked cakes to the queen of heaven) and Saint Augustine's City of God, which is to refute the notion that the Christians had offended the gods and brought about the sack of Rome.
And, besides the pious, you would have the pragmatic who wish to worship to make things safe, trying to honor both like the cautious Viking who put the Hammer of Thor on one side of a stone and the Cross of Christ on the other. (Hard-headed souls may think it beneath their dignity to cater too much to the gods -- but they know who they aren't catering to.)
And -- nothing or demons -- the Christians would have to hold demons, since the Old Religion has functional magic. Christianity is still taking over, without it. Which raises the little question of why? Writers whose sympathies are with the pagans seldom manage to take into account the most obvious thing about the two religions: that Christianity came second, and was adopted by the pagans.
Never mind your writing. Reading history will affect your reading.