Typical Workplace Conversation

I had so many tonight, but these two really were dim.

Customer comes to my window.
"How much is on my Oyster card?"
"One pound mate."
"Can I just put one more pound on please?"
"If that's all you want, no problem." I put a pound on his card.
"How much is on there now?"
"Sorry?!"
"How much is on there now?"
"One plus one is two mate."

And then this one while I was covering a meal break on the gates.

Customer is repeatedly touching something on the oyster reader, trying to get through the automatic gates.
"Excuse me, my oyster card's not working."
I take a look at it.
"That's probably because what you're holding is a Tesco's clubcard."