Goals are always good. If you want to set a goal where, by a certain date, you will be making a certain amount of money, it's fine, as long as you realize you're not finished. It's similar to the concept of the "New Year's Resolution"...I want to lose twenty pounds this year, I want to have $10,000 in my bank account by December 31, etc. The goal is clear, but all you have done is establish your success and failure scenarios. If the goal was twenty, and you only lost nineteen, it is a failure scenario by definition.
What I would suggest is to identify those things you need to do in order to achieve your goal, and focus your energy on your journey, rather than the destination. Losing twenty pounds is a great goal, but how will you stay on the path to your goal. You could decide to eliminate breads, pasta, and potatoes from your diet for the next 30 days. Once you establish the habit and see the result, it becomes easier to sustain the behavior over time, because you've narrowed your focus to a small change.
As far as money goals are concerned, they are, by nature, incomplete, because it will still require some action on your part to make that goal and that action is still undefined. A better money goal, in my opinion, is "I want to build a niche web site which will earn me $1000 per month by the end of the year." You've not only stated your goal, but you've also described how you wish to achieve that goal, which should help keep you on the path. Anything that is not contributing toward that goal should be a candidate for removal from your life, depending on how important the achievement is to you.