One day a school teacher wrote on the board the following:
When she was done, she looked to the students and they were all laughing at her, because of the first equation which was wrong, and then the teacher said the following,
"I wrote that first one wrong on purpose, because I wanted you to learn something important. This was for you to know how the world out there will treat you. You can see that I wrote RIGHT 9 times, but none of you congratulated me for it; you all laughed and criticized me because of one wrong thing I did. So this is the lesson...:
'The world will never appreciate the good you do a million times, but will criticize the one wrong thing you do...
But don't get discouraged, always rise above all the laughter and criticism.