I accept that bad language will appear in many of my books of choice. I don't like it, apart from when it may appear in a humorous context. For example, a hardened Londoner of either sex, aged and toothless, rolling their own cigarettes, slips in a naughty word or two when describing someone who's done them a wrong. That does seem natural and I'm not offended, and it can be funny. However, if the author, like some people I have worked with, drops the F bomb indiscriminately, then I'm turned off and will slot that name into my mental file for "Do Not Open Again".