I don’t usually get a lot of enjoyment from reading fiction that is laced with a lot of profanity. ((One of my favorite authors is Stephen King, and most of his works are notorious for foul language. I do love his tales, to the extent that I will read him anyway, and skip past the garbage as best I can.)) Such language is course and rude, and while the inclusion of such dialogue _is_ generally reflective of the way a lot of people talk, in my experience it usually only serves to detract from the telling of the story. I can deal with the occasional curse word here and there, placed strategically for emphasis, but as a general rule, I think that the inclusion of profane and curse words in a story is completely unnecessary.
It’s probably no secret that I’m something of an Orson Scott Card fanboy. Of all the authors I read, his books are always at the top of my list to read and to buy. ((I’ve even bought a couple of _Ender’s Game_ t-shirts and the mousepad.)) One of the things that so endears his writing to me is that he is able to create these rich, complex characters without ever resorting to profanity in their dialogue. I tend to think that writing cursing into character dialogue is a shortcut, a cheap way to demonstrate an aspect of your character’s personality. But I think that some of the best writing makes it very clear that your character just swore without ever specifying what it was that the characeter specifically said.
I’ve always felt that cursing is a rather “base behavior”:http://open-dialogue.com/blog/?p=194. I don’t think I’ve ever seen a place where its presence ever contributed anything useful or productive to the situation. It only seems to take and never give, and this is definitely true of literature. For me, at least, my reading experience is greatly enriched when I don’t have to filter and sort out all kinds of dialogue that makes me uncomfortable. So, keep the profanity out of your writing. I know I sure will.