Ohno said the way to think about perfection in manufacturing is to think about it as a supermarket: When a product is taken off the shelf, a factory behind the shelf makes another.

Of course it’s a crazy idea, but it shows you how to think. Goods should be made at the rate of customer consumption, that would be perfect.

In service organisations it is even easier to think for perfect: Perfect would be a system that organised immediately around each and every customer demand to fulfil exactly what the customer needed. Instead of a factory making a good to put on a shelf, the service agent ‘pulls’ what is needed to serve each customer.