In the business world, change has been a high-ranked and frequently mentioned trend for quite some time. Business textbooks, and thus business professors, teach us that change is the only constant in the world of professional performance. Sandwiched between the Industrial Revolution and the Internet era, the 20th century brought humanity quantum leaps in opportunities, inventions, productivity, change and leadership. One of the well-known leaders in business as well as government during the 20th century was Robert McNamara. Decisiveness is widely praised as a critical leadership quality. This was the case in the 20th century, and is still the case today. Assertiveness is brought in association with leadership, because it seems important for leaders to be outspoken and present solid reasoning when needed. In addition, 21st-century leaders have to be critical and creative thinkers because they are practically reinventing the entire concept of leadership in a different performance setting.