There's a local bar up here in northern Minnesota. They started charging a 2.5% surcharge. The bartender was defending the owner saying "last year Archie had to pay $50,000 in credit card fees!" I responded "do you know if he paid $50,000 in fees that means he had $2 million in sales?… Let that sink in for a minute considering he's paying you minimum wage". The guy stood there with a dumbfounded look on his face and you could see the gears turning.
Then I pulled out my checkbook and wrote him a check.