I know you are shocked by the title because if we don’t have a purpose how can we persist in life?!
When i first heard about this subject i was also surprised until i understood the reasons.
It is very important to aim for success and to work hard but the negative part is to set a very high goal that makes you feel upset and depressed in case you don’t achieve it. Also setting a specific goal to reach will blind you from seeing other opportunities and other goals. When you’re insisting on fulfilling a determined dream you will not get profit from the tools you have and you will refuse good opportunities that may give you a better future. For example if you’re dreaming of working on TV you start ignoring the chance you are offered to work in a radio because you want to arrive quickly to a high position instead of getting advantage from little chances to grow progressively and chase your dream.