Be persistent to the end - Steve Ballmer (Microsoft CEO)
Passion is the ability to transmit excitement to something and effort and perseverance is the ability to continue to do so. If you look at the companies that I started my business with, you will find that most fail. Even with companies that have been as successful as Microsoft, Apple, Google or Facebook, you need to know that all these companies have gone through turbulent periods.
You may have certain successes, but unfortunately your career has turned to smog. You apply a formula to the new idea, you consider it an innovation but it doesn't work. And that is the time to show your tenacity, relentless optimism and perseverance, personalities that will determine your success in the future.