And as the Assistant Manager's response indicates, the bad experience I had at Big Two apparently had nothing to do with the salesperson's abject disregard for courtesy or customer service. I guess I should not have expected to be treated with respect or professionalism. Again, I wasn't even offered the courtesy of a chair.
Thank goodness I walked out and found the Mark dealerships instead! They were easy to work with and provided an excellent, almost painless (it IS still buying a car, you know!) experience. When the time comes for another vehicle, I know exactly where I will (AND WON'T) go.