ALL COMMUNICATION RELATIONSHIPS, whether fleeting like a fund-raiser’s exchange with a donor or more lasting like a familial relationship, involve interdependence. (top left) © JoeFoxNewYork/Alamy; (top right) Carin Baer/© AMC / Courtesy: Everett Collection; (bottom left) © Focus Features/Courtesy Everett Collection; (bottom right) Kevin Mazur/Wireimage/Getty Images