If you died today, what would you regret?

Jon Cook is the Global Chief Executive Officer of VML, the world's largest advertising agency.

Jon died last October. As you'll hear, the fact he is still here to have this conversation required a set of circumstances so improbable that they would have strained the credibility of your favorite episodic drama.

But the fact he is still here, gives him, and those that meet him, a living and breathing teacher of what will really matter to us, when we reach our end.

As we age, our priorities and the emphasis of our life changes. We define success in more personal, more human ways.

And yet, when we become leaders we are judged - and we judge ourselves - against metrics that have limited shelf lives.

That will not change any time soon. If you do not deliver economic performance in a for-profit business, you will not be a leader for long.

But, and this is a big but, ask yourself now, what would you would regret if today was your last day on the planet? And then live a life that makes room for the behaviors that would change that answer.

Life and leadership are about choices. Don't wait until you're dead to make better ones.