In baseball, just a few moments can define your whole career: The bases loaded with two outs in the ninth inning, trailing by 3 runs in the world series. What a player does in that moment will likely define his whole career.
Maybe less dramatic, but these moments also happen in our ordinary lives. As we become a more experienced executive, we better recognize these moments and are more prepared. During my long international trips pitching potential investments, there are a lot of mundane work and small talk that goes into creating such a moment. What you do with such opportunities at the plate will define your career.
Life also gives you these critical moments in other ways. In love, such moments are no less important in defining your life. Some executives who perform well in business settings are often horrible at other life-defining moments regarding relationships with wives, children and other loved ones.
Time is constant and life can be short. Be deliberate during these moments as much as you can.