My friend Sarah is what you might call capable. She’s an emergency room surgeon in Salt Lake City; she’s the mother of a 5-year-old; and she has just completed her ninth marathon in as many years. On a Friday last February, while my husband and I sat in her ridiculously organized kitchen, she poured each of us a glass of wine as we asked her a million questions about her day. She seemed shocked that we were so interested in hearing her E.R. stories. Removing appendixes, stabilizing car accident victims, saving lives — all in a day’s work. She put up with all of our questions, and then said something I’ll never forget.