The habit of regret has never made much sense to me. It runs counter to my personal cosmology, in which all of my poor choices, and the bad as well as the good things that happen to me, brought me to exactly where I am now. Because the past and the future are only projections, it is in fact impossible to know in the present whether today’s big accomplishment is in fact meaningless trivia, or today’s impossible difficulty is the foundation of one’s future happiness. If I write something that feels amazing, or turns out to be meaningful, or have fun playing with my children, or am struck by a leaf turning color, then everything that happened to me in…