I curse. I curse in my daily life. A
lot. It's not for humor. It's not for effect, it's just part of my life. So while I get where many of you are coming from... it seems as weird to me for an author to go out of their way to
never curse (or worse, when they make up imaginary curse words) as it does when an author goes out of their way to curse
all of the time. I see no difference.
People curse. If your book has a fairly large cross-section of culture/characters/society in it and none of them ever curses... that's weird to me. If you have relatively few characters; all from a specific subset of society... then fine. Maybe none of them curse.