It's easy to make mistakes when calculating how much of a tip you should leave after a meal in a restaurant.
One man who accidentally underpaid a waitress felt so guilty that he went above and beyond to make it right.
He wrote the woman from Boston an apologetic letter and sent her the cash that he should have given her at the time.
The correspondence was posted to Reddit by a friend of the server involved.
Part of the letter read: "I was in for dinner Friday night with my wife, sister and brother-in-law... For some reason - perhaps rushing out to get to the show, I miscalculated your tip and ended up short changing you."
The kind stranger finished off the note saying: "Hopefully the $15 enclosed makes things right - I just hope it finds its way to you!"
Thankfully it did and the friend of the recipient said she was absolutely amazed by the thoughtful gesture.
Last September one lucky waitress in Michigan, USA was left a seriously generous tip from the table she had been serving.
Bre Snow served a group of American football fans food and drinks at the end of her shift.
She said: "It was more than a pick-me-up! After working so hard, to get a great pay-off from it really touched me."