There's an old story of the railroad employee who was asked why he was tapping the wheels of each freight car. "I don't know," he replied. "They just told me to tap them." It seems silly, but cases like that can be found in many everyday dealings with people. Workers are told what to do but not why.
Telling your workers why, giving them the information they need to do the job and do it well, accomplishes several objectives at one time. First, of course, it enables the worker to do the immediate job properly, which he can't do otherwise. But it also gives the worker an understanding of the purpose of his job as well as the feeling of being accepted. A worker who has all the facts will frequently thinking of a better way of doing it. After all, no one else will be as familiar with the job as he. No one else has had as much time to think about it. Furthermore, a well informed worker will apply more initiative and use his imagination thereby providing his job with his best talents.
There is still another important reason for explaining why. It minimizes the need to give direct orders. And few of us like to take orders.
(Stolen from
The Importance of "WHY")