You Just Can't Please Everybody

At an informal library event involving several authors, I got to
talking with a lively older woman. She asked what I wrote, and after
I'd told her, she asked, "Do you take the name of the Lord in vain in
your books?"
"Well," I said, "Some of my characters do use strong language,
including taking the name of the Lord in vain, but never just for
effect. I try to tune in to the way different people talk, and
anything they say needs to be appropriate for them and for the
situation in the story. They don't use four-letter words just for
effect. Same for violence and sex. They've all got to be integral
to the needs of the story."
The woman's smile got even brighter. "Oh, you can use all the
four-letter words you want in your books," she said. "And put in all
the gore and kinky sex you'd like. But I can't read books that take
the name of the Lord in vain."
Lesson learned. You write what's in you, the way it comes. Try to
tailor your books to please everyone, you'll be publishing blank pages.