What are Human flies?

“Human flies” is a term coined by Patricia in the novel, and gives the novel its title. A human fly is a person who, for whatever reason, cannot move beyond a tragic event or circumstance in his or her life, and as a result, lives their life based on that event, circling around it like a fly. Patricia and K2 come to realize that Olesen, and every other resident of the building, is a human fly. Patricia even concedes that she herself is a human fly.