I tried to buy a pizza from Dominos last week. Order online, pick up in person and pay with cash. Should have been simple, but it devolved into 5 minutes of Domino's employees trying to figure out "who's on cash?" (Had the credentials to open the cash drawer.) That person was apparently taking a smoke break, but when they came back it still took them another minute of furious hollywood hacker style keyboard pounding at the POS systems (accidental dual acronym of 'Point of Sale' and 'Piece of Shit'?) to open the cash drawer and give me my $1.20 change. Great job guys.
If you forgive me for being a little conspiratorial, I think point of sale systems must be designed to streamline credit card payments while artificially stalling cash transactions, as part of the financial industry's war against the cash economy.