is an excellent book by Jeffrey Liker (isbn 978-0-07-139231-0). As usual I'm going to quote from a few pages

One day a Ford Taurus mysteriously disappeared. It had been in the factory so they could try fitting it with some prototype mirrors. When it vanished, they even filed a police report. Then it turned up months later. Guess where it was. In the back of the plant, surrounded by inventory.

Extra inventory hides problems...
Ohno considered the fundamental waste to be overproduction, since it causes most of the other wastes… big buffers (inventory between processes) lead to other suboptimal behaviour, like reducing your motivation to continuously improve your operation.

…was that data was one step removed from the process, merely "indicators" of what was going on.

Building a culture takes years of applying a consistent approach with consistent principles.

It seems the typical U.S. company regularly alternates between the extremes of stunningly successful and borderline bankrupt.

Flow where you can, pull where you must.

When I interviewed [Fujio] Cho for this book, I asked him about differences in cultures between what he experienced starting up the Georgetown, Kentucky plant and managing Toyota plants in Japan. He did not hesitate to note that his number-one problem was getting group leaders and team members to stop the assembly line.

Every repair situation is unique.

The more inventory a company has,… the less likely they will have what they need [Taiichi Ohno]

I posit here that Toyota has evolved the most effective form of industrial organisation ever devised. At the heart of that organisation is a focus on its own survival. [John Shook]

You cannot measure an engineer's value-added productivity by looking at what he or she is doing. You have to follow the progress of an actual product the engineer is working on as it is being transformed into a final product (or service).

Everyone should tackle some great project at least once in their life. [Sakichi Toyoda]