When you visit St. Jude Children’s Research Hospital in Memphis, Tennessee, you expect to feel devastated. It starts in the waiting room. Oh, here we go with the little red wagons, you think, observing the cattle herd of them rounded up by the entrance to the Patient Care Center. Oh, here we go with the crayon drawings of needles. The itch begins at the back of your throat, and you start blinking very fast and mentally researching how much money you could donate without starving. Near a row of arcade games, a preteen curls his face into his mother’s shoulder while she strokes his head. Oh, here we go…