At United Parcel Service, Inc., rules are religion. Without them, UPS could never move 13.5 million packages to their destinations on time each day. But two years ago, Mark J. Colvard, a UPS manager in San Ramon, California, had to decide whether to buck the system. A driver needed time off to help an ailing family member but under company rules he wasn’t eligible. If Colvard went by the book, the driver would probably take the days anyway and be bred. If Colvard gave him the time off, he would catch flak from his other drivers. Coward wound up giving the driver two weeks, took some heat—and kept a valuable employee.