*Be aware that I will be using strong language, in the context of what is accurate, inaccurate, or distracting in certain settings.*
Last weekend, while Jason was playing a video game set in about 50 BC in Egypt, he complained that the swearing felt too modern and was therefor distracting. Frequently, the characters will use "shit" as an insult or taunt. This feels particularly egregious, as early in the game, an Egyptian word (I assume), "khet" was used by a character, and the translation of "shit" was shown in the dialog in parentheses after the word. "Why not keep using khet?" Jason wondered. Why bother to introduce that word at all if you're going to use modern English swear words instead?
But this incident got us discussing other words we find distracting in books and movies, and not all of them swearing. Another term being used in his game was "OK." That's one that really bothers me in historical pieces. OK is an American colloquialism that, while we can't pinpoint the exact first use and origin, it's generally agreed it began to be used in the mid 19th century - and even then, not to the broad extent it is today. So to see someone in 1st century BC Egypt, 18th century England, or other historical settings using "OK" in place of "good," "alright," or any other handful of synonymns is extremely distracting.
And, yes, I know that just the fact that the characters in the Egyptian game are conversing in English is, and and of itself, an anachronism, but we accept the idea that this is a translation of what they might be saying in a historical language. There is also the idea that certain phrasings, even in "translation" are too modern. A character in a historical period would be expected to say, "this is excellent news, my friend," rather than "that's totally rad, dude." (Unless you're watching a Bill and Ted movie.)
There are other words I find distracting, too. While "fuck" is actually a very old word, the way it is used can be distracting. Swearing is different in each culture and time period. Find something more historically accurate than "fuck you." "The Devil take you," is more appropriate in many European historical settings. Likewise, calling someone a bitch or a bastard - while those words have also been around for a while, there are all kinds of colorful swearwords for other periods. The point is, don't be lazy and insert your favorite insults - do a little research and find something that works for the period.
Similarly, slang and colloquialisms can be distracting. A year or two ago, I read a book that took place during World War II. The teen-aged characters in this book used the terms "cool" and "sexy." While I haven't done the research to see when each of those terms came into general use to mean "good," and "appealing" or "alluring," I'm pretty sure that the former emerged in the '50's and the latter emerged even later. Instead of "cool," they should have been using "swell," "keen," or possibly "neat." Off the top of my head, I'm actually not sure what a good substitute for "sexy" would be. But if I were writing a book that too place in the early '40's, I would find out.
In conclusion, gentles all, seek ye out thy most excellent and commendable insults, for thy father was a hamster and thy mother smelt of elderberries.