When in doubt, vary, change, solve the problem, seize the opportunity, experiment, try something new (consistent, of course, with the core ideology) … - Jim Collins

The Hedgehog Concept (Simplicity within the Three Circles). To go from good to great requires transcending the curse of competence. Just because something is your core business — just because you’ve been doing it for years or perhaps even decades — does not necessarily mean you can be the best in the world at it. And if you cannot be the best in the world at your core business, then your core business absolutely cannot form the basis of a great company. It must be replaced with a simple concept that reflects deep understanding of three intersecting circles.

Good is the enemy of great

What drives your economic engine. All the good-to-great companies attained piercing insight into how to most effectively generate sustained and robust cash flow and profitability. In particular, they discovered the single denominator — profit per x — that had the greatest impact on their economics.