How to scare off a customer

I walked into a auto repair shop today to get a tire leak fixed.   While waiting in the lobby I overheard the following conversation between a customer and a service representative:


Service Rep:  Okay, have you dealt with us before sir?  Would you be in our system?

Customer: I have, but it's been a while.

Service Rep:  How long are we talking?  There's a new computer system so you might not be in here anymore.

Customer:  I'm not sure how long it's been.  I'm sure Dennis set me up in there though.

Service Rep:  Well it wouldn't have been Dennis, he doesn't have access to set people up.

Customer:  Oh, well then he must have told someone to do it for him.

Service Rep:  HEY DENNIS DOESN'T TELL ANYONE TO DO ANYTHING, HE'S A NOBODY AROUND HERE AND PEOPLE IN THIS TOWN NEED TO START LEARNING THAT!!

(At this point my Hot Rod Monthly from 1997 that I found on my chair became far less interesting than events unfolding before me)

Customer:  Calm down buddy, I didn't mean anything by it.


And this was when the customer promptly left.  I'm not sure why this elderly gentleman needed to be held accountable for the internal squabbles of the shop or why everyone in the lobby needed to feel as awkward as a 15-year old boy who just discovered that his mom knows how to check browser history, but it was definitely more entertaining than I expected my tire repair experience to be.