“Tuesday 8.30: Board meeting.”  When estate agent Sally Shaw enters this appointment in her calendar, it means boogie boarding at Muizenberg in Cape Town with friends, not a meeting with suits. The “boogie broads”, mostly professional women in their silvery-blonde years, have been catching waves every week since February, even during storm warnings and when snow blanketed the nearby mountains.

Fun looks different for everybody but “true fun” combines playfulness, being connected, and immersed in the moment, says US science author Catherine Price. It is vital to wellbeing...