A large dog saw a pup chasing its tail and asked, "Why are you chasing your tail?"
Said the puppy, "I have mastered philosophy: I have solved the problems of the universe which no dog had rightly solved; I have learnt that the best thing for a dog is happiness, and that happiness is my tail. Therefore I am chasing it, I shall have it!"
Said the old dog: "My son, I, too, have paid attention to the problems of the universe in my weak way, and formed some opinions. I, too, have judged that happiness is in my tail. But, I have noticed that when I chase it, it keeps running away from me; but when I go about my business, it comes after me."