The hardest arithmetic to master is that which enables us to count our blessings.- Eric Hoffer
世界上最难的算术题是如何清点我们的祝福。

According to legend, a young man while roaming the desert came across a spring of delicious crystal-clear water. The water was so sweet, he filled his leather canteen so he could bring some back to a tribal elder who had been his teacher. 
据传说，一个年轻的男子在漫游沙漠途中看到一泉如水晶般清澈而可口的水。水的味道非常甜美，于是他灌满了他的皮水壶，这样就可以带一些回去，送给曾经是他老师的部落长老。

After a four-day journey he presented the water to the old man who took a deep drink, smiled warmly and thanked his student lavishly for the sweet water. The young man returned to his village with a happy heart. 
经过四天的旅程，他把水呈献给老人。老人深饮一口，和蔼地笑了笑，并深切感激学生赠予他甜美的水。年轻人怀着愉快的心情回到了村庄。

Later, the teacher let another student taste the water. He spat it out, saying it was awful. It apparently had become stale because of the old leather container.
后来，老师让他的另一个学生品尝水。学生吐了出来，说水太难喝了。它显然已经因为陈旧的皮革容器而变得不再新鲜。

The student challenged his teacher: "Master, the water was foul. Why did you pretend to like it?"
学生质疑他的老师：“师父，水是臭的，你为什么要假装喜欢它？”
学生质疑他的老师：“师父，水是臭的，你为什么要假装喜欢它？”