when I'm not working and I am forced to endure it, I step into the convo and tell the customer to go fuck themselves....usually results in the "who the fuck are you, this is none of your business" kind of response...that's when you can throw the "cunt" into it...with the "yeah it's not my business but seeing as how I'm a decent person and not the cunt you seem to be, I'm not gonna let you talk to them like that..."