Paris Métro tickets
On a visit to Paris, Sept. 21-29, 2010, several times my wife and I had problems getting Métro tickets at the smaller stations that had only one agent, who seemed only to supply information and did not dispense tickets anymore.
He’d tell us to use the automated machine, which only took chip-and-PIN cards or coinage. Some machines did take paper money, but it was hard to tell which were which.
We always tried to get a carnet of 10 tickets at a time to avoid having to repeatedly depend on the machines.