This is the story of a little boy who had very bad character. His father gave him a bag of nails and told him that each time he would lose his patience, he should nail a nail behind the door. The first day the boy nailed 37 nails behind the door. The following weeks, as he learned to control his temper, each time he would nail less nails behind the door. He discovered that it was easier to control his temper than to nail behind the door.
A day came when he could control his character during all the day. After informing his father, this one suggested that he should remove a nail each day he could control his character. The days passed and the youth could announce his father that there were no more nails to remove from the door.
His father took him by the hand and led him to the door. He told him,
'You have worked hard, my son, but look all those holes in the door. Never more it will be the same. Each time you lose your patience, you leave scars exactly as the ones you see here.'