Kwane Stewart stepped outside a Modesto, California, convenience store with his morning coffee and spotted a homeless man sitting with his back against the building. It was 2011, and the Great Recession had spilled a lot of unfortunate people onto the streets. A small dog sat in the homeless man’s lap. Stewart, a veterinarian at an animal shelter, noticed its scratched-off fur and chewed-up skin—telltale signs of an allergic reaction to fleas. He approached the man and offered to bring flea medication for the dog’s skin, a gift the man readily accepted.