They Suddenly Shut Up When They’re Given As Good As They Get

I have just put turned the sign on the door of our small shop to “Closed”. A customer comes up to the door as I am doing this and appears shocked that the door is locked.

Me: *Pointing to the closed sign* “Sorry, sir, we just closed.”

Customer: “Why the f*** have you closed?!”

Me: “Because I want to go the f*** home!”

Customer: “You can’t talk to me like that!”

I point to the sign just above the “Closed” sign:

Sign: “Please note: staff members have permission to talk to customers in the same manner that customers talk to them.”

Customer: “Well, f***.”

Me: “F***, indeed.”

The customer opened his mouth to say something but then thought better of it and wandered off.