Once upon a time, there lived a king who ruled over a prosperous country.
One day, he had to visit a distant part of his country. When he returned to his palace, he complained that his feet hurt very badly, as it was the first time that he had gone on such a long trip, and the path that he went through was very rough and stony.
He then ordered his people to cover every road in the entire country with leather. Definitely, this would need thousands of cows' skin, and would cost a huge amount of money.
Then one of his wiser servants dared to tell the king, "Why do you have to spend such a large sum to cover the roads ? Why don't you just cut a little piece of leather to cover your feet?"
The king was surprised, but he agreed - to make a "shoe" for himself.
There is actually a valuable lesson for life in this story: To make this world a happy place to live in, you better change yourself - your heart; and not the world.