But it just ain't so. Here are some of the difficulties. You don't know what you want, or what will satisfy you. The wish to be a soldier in battle is a classic example. Winning the lottery sometimes makes people wish they had never bought the ticket.
Tastes change with time.
Goals of making money will therefore change as your circumstances change. To some extent you can even forecast the change, and plan accordingly. When you are young and penniless you can predict that later in life you will earn much more, and a given sum will then mean less to you than at present. This may affect your current decisions about borrowing, and it may affect your planning with respect to the goals of earning additional income and doing community service three decades hence. Biological changes predictably alter your psychic states.