A young painter had just completed a beautiful painting. To get people ' s opinions about his painting skills, he put his painting at a crossing on a busy street and put up a board that read, " Gentlemen, I have painted this piece. Since I ' m new, I might have made some mistakes in my work. Please put a cross wherever you see a mistake. " When he came back in the evening, he was completely shocked to see that the whole painting was filled with crosses. He ran to his master and said to him, " I ' m useless and if this is what I have learned to paint, I ' m not worth teaching. " The master smiled and said, " I ' ll let you know that you are a great artist. Now go to paint the same painting again and give it to me. " Then they went to the same street the next morning and put the same painting exactly at the same place. Now the master took out another board which read, " Gentlemen, I have painted this piece. I might have made some mistakes in my painting. I have put a box with colors and brushed just below. If you see a mistake, pick up the brush and correct it. " Two days later, they came back to the place. The young painter was surprised to see that actually there was not a single correction. If you want to help people improve their behavior, you ' d better learn how to help people change their behavior, attitudes and skills. Also, always remember not to judge yourself by someone else ' s criticism ( 批评 ), because you are the best judge to judge yourself.