well, part of 17 and 18
example: I'm in a store and the cashier rings up the wrong price or doesn't ring it up and just puts it in the bag.this seems to happen almost weekly.
I don't want to tell them ( and I don't do it all the time) they made a mistake,cuz most people don't think they do make mistakes. so I walk out feeling a little guilty that I got something at a really good price, but eventually the thought subsides and I'm back to smiling.