Your why is the core belief of the restaurant. It's why the restaurant exists.
Great restaurants are built on passions, your why. Identify your why and write it down. Reference it when you are developing your menu, creating service standards, and building a marketing strategy.
This will create consistency in the way you run your business.
But don't just take our word for it; read the book, or at least watch the Ted Talk.
Simon Sinek
Book - Start with Why: How Great Leaders Inspire Everyone to Take Action
Ted Talk - How Great Leaders Inspire Action