If you don't stay abreast of the knowledge brought about by modern technology, the trends in the marketplace, and the discoveries in the field of health improvement, you will be left far behind or, at best, will experience only a portion of the progress that you're capable of experiencing. Having the desire to stay familiar with these changes and being open-minded about them ensures your continued success well into later life. You need to have a positive yet cautiously realistic attitude toward your own abilities and yourself. Knowing your capabilities and being realistic about your possibilities are starting places for success. For example, your chances of being a rocket scientist are slim if you flunked fifth grade math twice, so spending several years in college taking every course you need to be a rocket scientist but avoiding the math classes until the last semester is the same as planning to fail.
Unrealistic expectations are the seedbed of depression.
If you gained 20 pounds over the last three years, believing that you can lose all 20 pounds in three or four weeks is setting yourself up for a letdown. That goal just isn't realistic. You must have a sensible attitude toward positive thinking. Careful analysis forces you to realize that this idea is simply not true. For example, Reggie White, the All-Pro defensive end for the Green Bay Packers, is an upbeat, optimistic, enthusiastic, highly motivated positive thinker, but with him at 300 pounds, those assets would do him absolutely no good if he decided that he could change careers and make it as a jockey.