From the time she was a little girl, Abby Recker loved helping people. Her parents kept her stocked up with first-aid supplies so she could spend hours playing with her dolls, making up stories of ballet injuries and carefully wrapping “broken” arms and legs. Recker fondly describes her hometown of Cedar Rapids, Iowa, as a simple place where people are kind to one another. There’s even a term for it—“Iowa nice”—describing an overall sense of agreeableness and emotional trust shown by people...