A few years ago author Bennett Cerf was addressing an audience of doctors in San Diego. Afterwards one of these doctors told him about an operation he had performed on an ill‑tempered lady of about eighty.  The woman came through the surgery with flying colors despite all her dire prognostications. Nevertheless she became quite agitated when the doctor told her that in accordance with the rules of the hospital, she’d have to walk ten minutes the very first day after her surgery and would have to get out entirely in a week, since beds there were at a premium. 

Well, she had her ten‑minute walk the first day, tottering but under her own steam, lengthened it to twenty minutes the second day, and by the time she went home, was stomping all over the hospital‑‑including rooms where she had no r…