Why should we live every moment as if it's our last?

In response to my poem on lymphoma, someone recently asked me why I thought we should live every moment as if it was our last. This person pointed out that if we always did that, then one day we'd be right.

My answer is that we're always right. Every moment is our last moment, because every moment is unique. You can't live the same moment twice and each one of us only has a finite number of moments left. We can squander them or savor them. The choice is ours. But the fact remains that there are no ordinary moments and it's down to us to make them meaningful.