A daddy dog saw a his puppy chasing its tail and asked:

My Son, why are you chasing your tail that way?

I have studied philosophy and solved the problem of the universe, which no other dog before me had ever solved, – the puppy answered, – and I have found out that the best thing for a dog in life – is happiness, and that my happiness is in my tail. That is why I am chasing it, and when I catch it – I will reach happiness.

And the daddy dog replied:
– Son, in my young days I was also interested in the questions of the universe. I also thought that the happiness is in the tail and in the beginning I was also chasing it. But later I have noticed that anywhere I go and whatever I do, the tail was following behind me. And then I understood that I don’t need to chase it.