A Bakers Dozen
Back in the Middle Ages, bakers got so greedy they got caught shortchanging people. Kings made them add an extra loaf just to keep them from being kicked in the nuts.
The baker got caught shortchanging customers. He added an extra loaf just to save his balls.
King Richard made bakers give people 13 loaves to keep them from getting beheaded.
The bakers were so scared of getting punished they started giving people extra bread.