Who is Margaret from Richard Brautigan's Trout Fishing in America ; the Pill Versus the Springhill Mine Disaster ; and, in Watermelon Sugar and what is their importance?

Margaret is the narrator's former girlfriend, in whom he has lost interest. She, however, continues to pursue him, visiting his home, and banging on the door at all hours of the day and night. Margaret is described as a hyper-aggressive female. In the end, she sadly takes her own life.