When someone casts doubt on you and your ability to achieve a goal -- especially a far-fetched one -- how should you react? Should you hurl obscenities at them? Stoop down to their level and discredit their own goals or accomplishments? Absolutely not. The best course of action is to work harder than ever to achieve that goal -- and prove them wrong.  Over the years, people have doubted my ability to do everything from lose 30 pounds over the summer to land jobs for which there have been over 100 applicants. There's nothing sweeter than proving wrong those who write you off. And why would they? We can achieve anything we set our hearts and minds to. The naysayers are likely those who doubt their own ability to accomplish whatever goal you've set out to achieve, as well as their personal goals. They're simply projecting their own lack of self-confidence to you. Never stand for such behavior. If these individuals claim to be your friends, perhaps you ought to thin...