Hmm... It’s hard to find a proper answer for this question!
Passion is what you love to do (event without being paid). I think passion is one necessary condition to achieve success. Business owners, however, need to balance their passion to follow the plans set (sometimes not by themselves but the Board of Director). There are always difficulties in doing business. Thus, it would turn to the blind side when facing with those obstacle, you keep doing without seeing the solutions and with no tools for measuring its effectiveness.