A friend develops software in a big corporate. As part of his job he provides "help desk" support. Many of the problems are quite straight forward, but they're uncommon enough that it's easier for the dev team to provide support rather than the corporate helpdesk.
A while ago he got a problem that was really tricky.
One of the users called the help desk and said he couldn't log in into the application. My friend asked all the usual questions and it turned out the guy had followed the correct processes but it was telling him he was getting the answer to the "personalised secret question wrong".
You know the sort of thing I mean: when you setup your account you put in the question and an answer. So for me, I might put in, "Which country were you born in?" and "New Zealand" and then when I forget my password the software asks me "Which country were you born in?", I type in "New Zealand" and next thing you know I'm allowed to change my password and get in.
But it wasn't working.
No one else was having this problem.
After a while, my friend, said, "Now don't tell me the answer ... but can you tell me your question?"
"Sure", said the guy, "It's asking me how much change I have in my pocket."