It seems I have acquired a reputation. I have been handing out dog treats for three months. Every day, I take the same trail, and every day, I meet many of the same customers. Dogs have an amazing memory when it comes to getting a treat—particularly from a stranger. One dog is not allowed treats. “No treats!” his owner says. Before I knew her better, I suggested, “Maybe he’d like a treat?” “Wouldn’t we all?!” she said. (That lady sounded like she could really use a treat.) But she is the only one. There is a Bernese Mountain dog, appropriately named Bernie, who always gets ...