Have you heard the story of a man who wanted water and so started digging the earth? This is what he did: He chose a spot at random and dug there for some time, but didn't find any water there quickly enough. He moved to another place at random, and started digging there. There too, he dug for some time, but didn't find any water quickly enough. Then he picked up another spot. He gave up that spot also for another one. In that way, he kept on choosing newer and newer spots and giving them up one after the other. By the end of the day, he still had no water. Next day, his wife came along, chose a spot carefully after much enquiry and study, and started digging there. At first, she didn't find any water, either. But she kept on digging at the same spot, and didn't leave that spot -- because she knew she had chosen the spot wisely and was sure to find water there. And in less than half the time her husband had taken to dig all the pits, she dug up a deeper bit and got water out of it.