Biggest misery of human is when he wants something desperately, but once he gets it realise that he did not want it. This is also called addiction and is completely opposite of being a rational human being. Also, nature of human who has fallen in this trap will be he will always keep on wanting this and will never enjoy getting it. Want is only till you get it and thats the true nature of addiction and not really passion. He will end his life just doing this as his only focus.