If you feel afraid, you can make yourself courageous by acting courageous. If you are feeling unhappy, by deliberately acting happy you can induce happy feeling. If you are lacking in enthusiasm, by simply acting enthusiastic you can make yourself enthusiastic.
Norman Vincent PealeThere is a basic law that like attracts like. Negative thinking definitely attracts negative results. Conversely, if a person habitually thinks optimistically and hopefully, his positive thinking sets in motion creative forces - and success instead of eluding him flows toward him.
Norman Vincent Peale