Cost of a glass of water

Once upon a time, Alexander The Great came to India. There he met a saint. Seeing Alexander, the Saint started laughing and seeing this, Alexander got angry and said that "This way you are insulting me. Don't you know I'm Alexander the Great? The saint again started laughing loudly and he said to Alexander "I do not see any greatness in you. I feel very sorry for you."

Alexander asked, "are you mad?". I had conquered the whole world. Then the saint said, "it is not that big deal, yet you say then Let me ask you a question. Suppose you got stuck in a desert and there is no source of water. and then someone offers you water but for that one glass of water you have to give something to that person so what can you offer?

Alexander said, I will give half of my kingdom for a glass of water, then the saint said, "if I denied". Then Alexander said "In such a bad condition I will give my entire kingdom. The saint then started laughing and said, "O Alexander, now the total value of your kingdom is equal to one glass of water and still you are very proud of that." Hearing this, Alexander's pride was destroyed.