To curse or not to curse.

I've often frowned on whether a book is proper if colorful language or "Cursing" should be included in a book. The "F" word to me, always seemed to darken a book, but sometimes it's needed or justified to deliver the scene. The newest book I'm writing "An Unusual Hit" has Gangsters and a Racist Black street thug. Somehow writing "Okay you mugs, you done made me angry, therefore, I will have to shoot you full of darn holes."...seems weak. More appropriate would be the next line full of colorful darkened language which I prefer not to include in this Blog. I've read many books that include this type of language, and it did not seem to dampen readers pursuing the book. I've went through and cleaned it up best I could, but without the dark language it just doesn't deliver. Hopefully folks won't bash me when the book comes out. It's a rather large book with an eerie twist at the end.