“There is nothing quite so useless, as doing with great efficiency, something that should not be done at all.”

“There is surely nothing quite so useless as doing with great efficiency what should not be done at all.”

“There is nothing so useless as doing efficiently that which should not be done at all.”

“A person can perform only from strength. One cannot build performance on weakness, let alone on something one cannot do at all.”

“If you want something new, you have to stop doing something old”

“Efficiency is doing the thing right. Effectiveness is doing the right thing.”

“We all have a vast number of areas in which we have no talent or skill and little chance of becoming even mediocre. In those areas a knowledge workers should not take on work, jobs and assignments. It takes far more energy to improve from incompetence to mediocrity than it takes to improve from first-rate performance to excellence.”