This is a timely editorial, coming on the heels of a recent one of yours where you gave a breakdown of how you spent your time -- number of trips, speaking engagements, and, most importantly in my view, number of volleyball tournaments of your daughter that you attended.  I thought to myself that you had an upside down life and what would be most important to me showed up lowest on your 'time spent on...' list.  When you are 85 (hoping you make it that far), do you suppose you'll look back and say 'if only I had worked a little harder, spoken at a few more conferences, written another book...'  I doubt it.  
But this is all very personal, and what is important to one person is less important to another.