In his famous book, The Strangest Secret, Earl Nightingale stated, you are what you think. You become what you think about most of the time. He believed that if a person only feeds his mind with negative thoughts, he will experience life through a dark lens.
Small things that shouldn't affect him will ultimately become bigger than they really are because their mind is focused on the worst possible outcome rather than the best. He talked about how a person who lives with mostly negative thoughts will focus his mind on all his problems rather than the opportunities before him.
