So you can have something to do in life. If you don't set goals, you'll be living with your parents at 40. You won't have a job. You'll be playing Call of Duty or Mindcraft nonstop for ten hours a day. You'll be counting every single dust bunny in the house until you have each one documented and described in enough detail to make Jules Verne would go insane. A goal is what makes life good. A girlfriend or boyfriend is good. A job with good pay. Your own house. A Cadillac. All of these are essential and helpful in life. These things will help you prosper.