I think of the pottymouth as me doing people a favor, really. If someone's the type to get offended at my tendency to treat 'fuck' as an all-purpose word, they're probably also the type who will not appreciate any of our general tone/register of communication! So my complete failure to ever behave like a proper serious-business grownup adult for more than five minutes is really a benefit. 

(That's my story and I'm sticking to it, anyway.)