The pursuit of efficiency — getting the most with the least investment of energy, time, or money — was once a laudable goal, but being effective in today’s world is less a question of optimizing for a known (and relatively stable) set of variables than responsiveness to a constantly shifting environment. Adaptability, not efficiency, must become our central competency.
Stanley McChrystal. Team of Teams. Penguin, New York, 2015 (p. 20).