A line in Oliver Twist
, by Charles Dickens
. You'll often hear it in a variety of places.
When Oliver lives in an orphanage, the officials there conspire to give the cheapest possible meals to the children, pretty much starving them.
Oliver, on his first day there, finishes the whole thing in about a gulp. It's got less calories than water, the way the author describes how bad it is. He goes back up to the line, holds out his bowl, and asks meekly "Please, sir, can I have some more?"
The incredulous man punishes Oliver severely for having the audacity. The officials swear that he'll be hung one day. The adults tell all the children to keep away from him, as he's bound for hell. There everything takes a turn for the worse, although it was pretty bad to begin with.
The whole thing is a satire, but everyone reading it is supposed to feel bad for him.