I suspect it's largely a matter of maturity (**shudder**), but I have really cleaned up my language in recent years. I still revert when provoked, but I've all but eliminated foul language from my everyday conversation. There are so many better words to use to evoke feelings. it's just that they usually have more than one syllable, and that does throw a lot of people off.
I can almost count on one hand the number of times I ever heard my dad swear. He just wasn't the type to cuss gratuitously; he had to be really upset. Mom would occasionally let a word out, but never of her own volition. She would 'quote' someone else instead. I think she enjoyed the irony of it, but she, too, really didn't curse just for the sake of cursing.
I was at the food court on the mall recently, and there were a couple high school-aged kids sitting near me having a conversation, and typical of their age, they were throwing f-bombs and other epithets around very liberally. They weren't being rowdy or acting hostile; they were just talking like the vast majority of kids their age these days. I interrupted them and told them it was fine for now, but when my wife showed up, I wanted them to clean up their language, "or there was going to be a big, f***ing problem." They didn't wait for Lois to show up, and after a minute or two, moved to a table out of earshot.
When I got out of the Navy, I cursed like a sailor.......WAIT!! I WAS a sailor. Lois finally cured me of some of the less savory tendencies I had towards language. It took a while, though.
I still slip that "s" word at times under my breath, but my hubby cured me of the bad language when we started dating. I can still fall into that sometimes as it has saved my life when I've been attacked in NY. No one expected a little Chinese girl to scream out such vile language. It gave me a second to get away or to kick them where it hurts. 
