Yes, it happens - we have to respectfully break-up with our customers sometimes. It's never fun, and it upsets everyone. But you have to know where your line is in the sand.
Yesterday, I was called upon to do just that. A small mix-up in communication (from our perspective, no mix-up, but that's a story for another time!) resulted in the customer yelling, swearing and carrying on to the point where he not only alienated our two Design Resources staff, but the installer also insisted he would NEVER do work for that client.
I called the gentleman and as he was going on about our lacking service and attention to OBVIOUS details - I had to inform him that it was not acceptable to swear at THREE of our people over the relatively small issue at hand.
This is my favorite part, and the reason I wanted to share this: He hotly replied, "I swore at TWO of your people, not three!". (Isn't that like the sibling who tells his Mom, "Yeah, well he hit me back first!")
... Sending him a refund... (and besides, nobody refers to my momma as "THAT woman!")