One bad turn deserves another.
乌鸦和水罐
The Crow and the Pitcher
一只乌鸦口渴难忍，看到一只水罐，就兴冲冲地飞过去了。可是飞到水罐旁边，乌鸦才发现水罐的水少得可怜。乌鸦绞尽脑汁，想了很多办法，可是依然喝不到水。这时，乌鸦已经筋疲力尽了。偶然间，他看到水罐旁边有很多小石头，乌鸦终于想到了一条妙计。他用嘴衔住小石头，然后将它们一颗颗地放进水罐里，这样石头就会占据水的空间，水面自然上升了。就这样乌鸦如愿以偿地喝到了水。
自我需要是成功的动机。
A Crow perishing with thirst saw a Pitcher，and hoping to find water，flew to it with delight. When he reached it，he discovered to his grief that it contained so little water that he could not possibly get at it. He tried everything he could think of to reach the water，but all his efforts were in vain. At last he collected as many stones as he could carry and dropped them one by one with his beak into the Pitcher，until he brought the water within his reach and thus saved his life.