If we deliver on time, but the product has defects, we have not delivered on time.
In a true zero-defects approach, there are no unimportant items.
Most things don't work like they are supposed to work.
It is not possible to know what you need to learn.
It isn't what you find, it's what you do about what you find.
We must define quality as conformance to specifications if we are to manage it.