Cats and happiness

Recently has read a class parable about cats.
Once the old cat, has met a young kitten. The kitten ran round and tried to catch the tail.
The old cat stood and looked, and the young kitten all turned, fell, rose and again chased a tail.
— Why you chase the tail? — The old cat has asked.
— To me have told — the kitten — that my tail, this my happiness has answered, here I and try to catch it.

The old cat has smiled, as old cats are able to do it only and has told:
— When I was young, to me too have told that in my tail, my happiness. I ran many days behind the tail and tried to seize it.
I did not eat, did not drink, but only ran behind a tail. I fell flat-out, rose and again tried to catch the tail. Of what that the moment I have despaired and have gone.

Has simply wandered aimlessly. Also you know that I suddenly have noticed?
— What? — With surprise the kitten has asked.
— I have noticed that where I would not go, my tail everywhere goes with me.