When she was 80, we bought her 80 presents. It took a while to find 80 things that an 80-year-old didn't already have and could eventually use, but we did. We bought shortbread and jelly and notepaper and stamps and dusting powder and assorted teas, and wrapped all the gifts in silver foil and tied them with white bows then placed them in and around a pink hatbox. The presents, by their sheer number, made 80 look inviting. My mother-in-law, surrounded by family and friends, sat in the living room and talked and laughed as she unwrapped each present…