David’s sister, Cassidy, has two children, Daniela and Tyler. From the moment our pool was finished, she made it clear she considered it a family amenity, with her family being the primary beneficiaries. At first, I didn’t mind. Family is family, right? What began as occasional weekend visits quickly morphed into a standing summer appointment. Every Saturday and Sunday, from Memorial Day to Labor Day, Cassidy would arrive with her kids, an entourage of their friends, coolers of food, and an air of breezy entitlement.