“Management may be extremely difficult and important even though managers are indistinguishable,” he writes. “It is hard to tell the difference between two different light bulbs also; but if you take all the light bulbs away, it is difficult to read in the dark.”
“Good leaders can make a small positive difference; bad leaders can make a huge negative difference,” Stanford’s Jeffrey Pfeffer told Fortune in 2006.
The article is full of references to actual, empirical studies of the impacts of leaders & managers, all pointing to the negligible affect of good leadership and the catastrophic effect of bad leadership. Perhaps a good general leadership motto is “Do no harm”.