On a flight today from Colorado Springs to Houston on a small regional jet, I asked the flight attendant for a can of Diet Coke. She prepared to hand me an unopened can and at the moment of handoff, we hit a bit of choppy air. The can missed my hand, hit the edge of the cart, did a triple somersault in the pike position, hit the aisle of the plane and rolled three rows back, where a laughing fellow passenger retrieved it and handed it back up towards me.
Amidst the jovial comments on what that can of soda would do, the flight attendant kindly offered to swap it out for one that had not had such a rough ride. And, in a rare moment of clarity, I declined. "Why would we want to give this to someone else who is unaware of its state?" I posed to her. She looked at me a bit funny and I laughed with her, muttering something about PV=nRT, the only equation I remember from college chemistry. Yet I meant it and she accepted my odd reasoning and I kept the can. And, with a cautious, gentle lifting of the tab and two inelegant though effective slurps off the top of the can, I had my soda. No one else got sprayed. The flight attendant didn't have to explain anything away.
I got thinking about this brief incident. What happens when we pass along a piece of work we know is defective? Especially if it isn't obvious from the outside? Like a shaken-up can of soda? Yeah...we simply create grief down the line. Someone else has to clean up the mess. What happens, alternatively, when we don't pass along work we know is defective? Very often, as in this case, the operator can correct the error. And it cuts off the chain of error downstream.
There are defects in this analogy. But the principle of refusing to pass along a known problem holds in any lean system. I hope you will think twice today about passing along your Fizzy Coke.