In my late 20s, in the ladies room of the local animal shelter where I was a volunteer, I overheard an attractive woman in her 50s say she’d decided to move to Scottsdale simply because she liked it there. Wait, who does that? Intrigued, I asked her to meet me for coffee and tell me more.

Her name was Maggie Graves. She and I became friends—mostly through letters, since she moved shortly after we met. (Quaint, right? But this was the pre–iPhone era, kids. Things were cryptic.) I’m ashamed to admit that I put off visiting Maggie because I wanted to lose a few pounds. I was too busy to write (or thought I was), and we lost touch. A few years later, I tried to reconnect. Maggie had sold her home at 10570 E. Morning Star Drive. Hoping to get her new address, I tracked down her realtor. “I’m sorry to tell you this,” she said, “but Maggie committed suicide.”

I keep a photo of Maggie on my desk. It serves as a continual reminder to me that life doesn’t wait. You can’t always pick up the phone or go for a visit later. Sometimes “later” is too late. Most of us learn this the hard way. And regrets like this one—a seemingly small action or inaction—can haunt us. This episode of the podcast Hidden Brain explains that this kind of stewing over something you can’t change is called “ruminative regret,” because you turn it over and over in your mind.

If you’re writing your own obituary, share some of your hard-won wisdom with the rest of us when you go. What regrets do you have that we might learn from? What would you do over or take back or follow through on? If you’re writing an obituary for a loved one, what do you think that person most regretted?

In that snapshot I have of Maggie, she sits on a red rock ledge in the Sedona desert, waving to the camera as if she knew what lay ahead. How often I think of her…How many others must still be thinking of her, too? My visit wouldn’t have changed things for Maggie. But maybe if she’d known how much she’d be missed by so many people all these years later? Well, who knows…