Albert Camus says:" An achievement is a bondage. It obliges one to a higher achievement."To my mind, it is true. If you have achieved something, then the others will wait from you something new and great. They will demand you to be better. And you also will not be satisfied with your success, you'll think that it's not an achievement and you must do something great. Also it's true that when you have done what you wanted, you become unhappy, because then you think that it's not important and you may have done it better. Then you begin reproach yourself. Strange people we are, aren't we?