When a worker has reached a stable state, further training will not help him.
The most important things cannot be measured.
Stamping out fires is a lot of fun, but it is only putting things back the way they were.
People copy examples and then they wonder what is the trouble. They look at examples and without theory they learn nothing.
The job can't be finished only improved to please the customer.
It is a mistake to assume that if everybody does his job, it will be all right. The whole system may be in trouble.