To spend a few minutes with people is simply not productive. If one wants to get anything across, one has to spend a fairly large minimum quantum of time.

The manager who things that he can discuss the plans, direction, and performance of one of his subordinates in fifteen minutes – and many managers believe this – is just deceiving himself. If one wants to get to the point of having an impact, one needs probably at least an hour and usually more.

And if one has to establish a human relationship, one needs infinitely more time.

Peter F. Drucker
The Effective Executive (New York: Harper, 2006), 29