Pies can be heartbreaking. They are burdened with the heavy weight of all-American nostalgia. That is a lot to shoulder. A pie loaded with berries or apples or nuts or custard can be uniquely disappointing—at once soggy, oversweet, tasteless, and, yes, sad. I can think of no other dessert that has been mined so deeply to reflect a grandmotherly aura, and yet so many pies do Grandma wrong.