Man is made by his belief. As he believes, so he is! You are what you think you are. Your thoughts make and define you. If you think you’re a happy person, you become happy. If you let sad thoughts take over your mind, you tend to become a sad person. If you feel that you will nail a presentation in a meeting, then chances are that you will. However, if you’re not prepared and feel nervous then you might make a blunder.