there once was a boy who had a bad temper. his father gave him a bag full of nails and told him that every time he losses his temper, he must hammer a nail into the wooden fence in front of their house. 

The first day the boy had driven 37 nails into the fence. over the next few weeks, as he learned to control his anger. the number of nails hammered into the fence daily gradually dwindled down. he discovered it was easier to hold his temper than to drive those nails into the fence.

Finally the day came when the boy didn't lose his temper at all. he told his father about it and the father suggested that the boy should pull out one nail for each day that he was able to hold his temper. The day passed and that boy finally was able to tell that all nails were gone.

his father took him by the hand and led him to the fence.
the father said

• "you have done well my son, but look at the holes in the fence. the fence will never be the same. when you say things in anger, they leave a scar just like this one"
• "you can put a knife in a man and draw it out. it won't matter how may times you say i'm sorry, the wound is still there"