Joan B. was among my wife's circle of close female friends. She was in her mid-40s, active, intelligent, happily married with two good kids, keeping a comfortable suburban home, and generally living the prototypical suburban middle-class life. Always busy, she often expressed the desire to travel to various exotic places, but dismissed those yens as impractical and relegated them to the "maybe later" category.

Sadly, for Joan, "maybe later" never came. One day, without any warning symptoms, she suffered a catastrophic brain hemorrhage; after two months in a coma, doctors and family reluctantly decided to remove life support.

Since that time, whenever any of that group of friends discussed delaying some adventure or trip because of day-to-day pressures and preoccupations, the others always countered with "Remember Joan" and urged her to go ahead while she could. My wife and I, too, often used this rationale -- for which I am very grateful, because we took some great Joan trips before a stroke grounded my wife for the remainder of her days.

Mortality gives us a sense of urgency.

You never know when something catastrophic might happen to your brain.

Remember to do things while you still can.

It's not just death that is a concern. Soon after my miraculous recovery from a brain hemorrhage, I had the experience of touring New York with a friend who was in a wheelchair. I was never so happy to have full mobility! All those adorable little restaurants and boutiques in half-basements and converted brownstones and just one step down? 80% of them are basically unworkable without full mobility. I literally walked as far and as fast as I could for weeks afterwards, and danced as much as I could... just because I still could.