I remember back in about 2000, the first time I tried to top up my pay-as-you-go phone. I duly purchased a 10 quid top-up card from the supermarket, scratched off the opaque coating over the secret code, and tried to follow the instructions. But the instructions wanted me to enter the secret code followed by the hash key, and I couldn't find the output of a one-time function applied to the secret code anywhere on the card... It took a call to the operator's support line and much mutual confusion to figure that one out.
Biting the hand that feeds IT
