Over the last 15 years, as a geriatrics and palliative care doctor, I have had candid conversations with countless patients near the end of their lives. The most common emotion they express is regret: regret that they never took the time to mend broken friendships and relationships; regret that they never told their friends and family how much they care; regret that they are going to be remembered by their children as hypercritical mothers or exacting, authoritarian fathers.

And that’s why I came up with a project to encourage people to write a last letter to their loved ones. It can be done when someone is ill, but it’s really worth doing when one is still healthy, before it’s too late.

It’s a lesson I learned years ago from a memorable dying patient. He was a Marine combat veteran who had lived on a staple diet of Semper Fi and studied silence all his life. A proud and stoic man, he was admitted to the hospital for intractable pain from widely spread cancer. Every day, his wife visited him and spent many hours at his bedside watching him watch television. She explained to me that he had never been much of a talker in their 50-plus years of marriage.

But he was far more forthcoming with me, especially when it became clear that his days were numbered. He spoke of his deep regret for not having spent enough time with his wife, whom he loved very much, and of his great pride in his son, who had joined the Marines in his father’s footsteps.