He decides not to tell anybody and keeps quiet.
At the end of the following month when he opens the cheque, he sees that he’s been underpaid by £2000.
Fuming, he goes to have it out with his employer. “Sir, I think you’ve made a mistake on my cheque.”
“And how do you figure that?” his employer asks.
“It seems I’ve been underpaid by £2000.”
“No disrespect Sir, but I want my money.”
“Last month I overpaid you by £2000 and you didn’t complain so why now?”
“Well Sir, thing is I don’t mind if you make a mistake once but if it becomes a habit I have to say something.”