A few weeks ago, my husband asked me if I had a tissue. “Sure,” I said. Of course I had a tissue. I had a backpack full of useful stuff, right? I dug through my bag, rummaging for a tissue underneath discarded grocery lists, schedules, and reminders. Past about twelve pens. Beyond my wallet, a few random toys, crumpled wrappers, receipts, a couple small books, and a collection of brochures we’d picked up over the past several months. Not a tissue in sight. But aha! There was