Buying rail tickets online and via the machines irritates me so I usually opt for the ticket window. Rolled up there today and asked for "2 off peak day returns for West Brompton no tube etc etc" (its in London)
"£69.39" he said
"That's a lot more than I usually pay," i replied in surprised tones
Frantic computer key tapping went on behind the glass. Then
"£33.00 please," he said. "You have to be careful with the computer - if you put in West Brompton instead of Zone 1/2/3 then it works out completely differently."
"Mm, I blame the programmers," I said. "Every time."
But really, isn't it is a good job I was concentrating.
Moral of the story is to check the approximate price you expect to pay before you go to the station. Those programmers will get some things wrong.
NEW - "New Limerick Thread II 2016" (following New Limerick Thread
Lending/gifting money to children

(I think!)
e.g. London-Carmarthen cheaper if you buy a ticket from the ferry company London to Wexford
and said that I thought he was a lovely man, thank you and dug in my purse for my railcard. Very embarrassingly he pointed out that it was just over a month out of date and he could charge me up to four times the full value of the journey I was making as a fine. I'm convinced that it was only because we had just had a fleeting moment of friendly banter that he just gave me a warning to get it renewed.