Startup, I have always been a bit of a troublemaker at the companies at which I have worked, pushing for rapid iteration, data-driven decision making… - Eric Ries

A famous example is the chain Potbelly Sandwich Shop, which today has over two hundred stores. It began as an antique store in 1977; the owners started to sell sandwiches as a way to bolster traffic to their stores. Pretty soon they had pivoted their way into an entirely different line of business.

What if we found ourselves building something that nobody wanted? In that case what did it matter if we did it on time and on budget?

This is true startup productivity: systematically figuring out the right things to build.