Passion is an intense emotion, a compelling enthusiasm or desire of doing what one loves. Successful people win because they have passion & they love what they do. It is passion which inculcates virtue of a very strong desire to succeed. Interest is something which is ephemeral and transitory, while passion is something which keeps you on your toes. You are ready to let go anything for your passion. While you can have several areas of interest at a time but Passion is one.