President Jimmy Carter has shared a powerful encounter he experienced as a young naval officer; an event that he says shaped his life. In order to be considered for an officer’s position on a nuclear submarine, the candidate first had to be interviewed and approved by Admiral Hyman Rickover, who at the time was head of the United States Nuclear Navy. Here is how President Carter described the interview:

I had applied for the nuclear submarine program, and Admiral Rickover was interviewing me for the job. It was the first time I met Admiral Rickover, and we sat in a large room by ourselves for more than two hours, and he let me choose any subjects I wished to discuss. Very carefully, I chose those about which I knew most at the time — current events, seamanship, music, literature, naval tactics, electronics, gunnery — and he began to ask me a series of questions of increasing difficulty. In each instance, he soon proved that I knew relatively little about the subject I had chosen. He always looked right into my eyes, and he never smiled. I was saturated with cold sweat. Finally, he asked a question and I thought I could redeem myself. He said, “How did you stand in your class at the Naval Academy?” Since I had completed my sophomore year at Georgia Tech before Annapolis as a plebe, I had done very well, and I swelled my chest with pride and answered, “Sir, I stood fifty-ninth in a class of 820!” I sat back to wait for the congratulations — which never came. Instead, the question, “Did you do your best?”

I started to say, “Yes, sir,” but I remembered who this was and recalled several of the many times at the Academy when I could have learned more about our allies, our enemies, weapons, strategy, and so forth. I was just human. I finally gulped and said, “No, sir, I didn’t always do my best.”

He looked at me for a long time, and then turned his chair around to end the interview. He asked one final question, which I have never been able to forget — or to answer. He said, “Why not?”

I sat there for a while, shaken, and slowly left the room.

This encounter caused Carter to completely alter the direction of his life, and later inspired his best-selling book Why Not the Best? Admiral Rickover’s powerful words to Carter have made me wonder if I have even come close to doing my best in this life, and whether, in reality, anyone ever really does his or her very best? Rickover’s final question to Carter seems very pointed and appropriate: “If you have not done your best… why not?”

Best-selling author and noted business consultant Stephen Covey takes a slightly different approach to confronting this same issue. He poses a series of questions:

What is the one activity that you know if you did superbly well and consistently would have significant results in your personal life? And what is the one activity that you know if you did superbly well and consistently would have significant positive results in your professional or work life? And if you know these things would make such a significant difference, why are you not doing them right now?

Covey concludes there is one primary reason we seldom pursue these activities: We do not consider them with any real sense of urgency. We most likely recognize that they are important but just not pressing. Therefore we procrastinate, with the justification “I will get to it later.”

I am not sure we fully understand that the important activities of life so often don’t act on us; we must make clear and conscious choices to act on them. This lack of understanding is perhaps why so many of us spend our lives reacting to the urgent demands of life and then wonder why we’re unable to focus on the important activities that will make a significant and lasting difference. As a result, in our day-to-day decision making, the “urgent” seems to dominate over the “important,” and thus we end up with very little personal growth and, at best, a mediocre life.

I believe Covey is right. We have this tendency to drift through life without pursuing meaningful objectives. Research indicates that most people in Western societies do not have a clearly defined strategy or mission for their lives. They live reactively. Their lives become nothing more than a response to the circumstances that are presented to them each day, increasingly in the form of tweets, posts, and emails. Modern people seem to be bound to a frenetic lifestyle, merely doing what is most urgent and immediate.

This reflects what Pulitzer Prize-winning novelist John Cheever said many years ago: “The main emotion of the adult American, who has all the advantages of wealth, education, and culture, is disappointment.”

Too many adults, particularly as they near the end of their lives, experience the awful pain of regret as they reflect on a life that could have been.

Several years ago, Bob and Judy Fisher, a husband and- wife team living in Nashville, Tennessee, wrote an interesting book on the subject of long-term thinking. Their book, entitled Life is a Gift, focuses on, among other things, a life of regret. The Fishers interviewed 104 terminally ill patients, all of them under hospice care. In each case there was a recurring theme:

So many people realized too late that there was a significant gap between the things they ought to be doing in their lives, and the things they actually did.

Now contrast this with the life of author C. S. Lewis. If you have ever read about Lewis’ personal life, you will have discovered that he led a very well ordered and disciplined life. He maintained great relationships and truly lived an exceptional life. Lewis passed away at age sixty-five, yet a week before he died, he said to his brother Warren: “I have done all that I was sent into the world to do, I am ready to go.”

What a stark contrast with the hospice patients the Fishers interviewed, who so painfully revealed the regrets in their lives. Aren’t the words of C. S. Lewis what we would all like to be able to say at the end of our lives?

I believe that we’re all capable of doing just that, but it all depends on what we are doing right now.

Richard E Simmons III is the founder and Executive Director of The Center for Executive Leadership and a best-selling author.