Communication among healthcare professionals is a focus for research and policy interventions designed to improve patient safety, but the challenges of changing interprofessional communication patterns are rarely described. We present an analysis of 756 preoperative briefings conducted by general surgery teams (anesthesiologists, nurses, and surgeons) at four urban Canadian hospitals in the context of two research studies conducted between August 2004 and December 2007. We ask the questions: how and why did briefings succeed, how and why did they fail, and what did they mean for different participants? Ethnographic fieldnotes documenting the coordination and performance of team briefings were analyzed using Kenneth Burke's concepts of motive and attitude. The language and behaviour of participants were interpreted as purposive and situated actions which reveal perceptions, beliefs and values. Motives and attitudes varied both within and across sites, professions, individuals, and briefings. They were contingent on the organizational, medical and social scenes in which the briefings took place and on participants' multiple perceived purposes for participating (protecting patient safety, exchanging information, engaging with the team, fulfilling professional commitments, participating in research, and meeting social expectations). Participants' attitudes reflected their recognition (or rejection) of specific purposes, the briefings' perceived effectiveness in serving these purposes, and the briefings' perceived alignment (or conflict) with other priorities. Our findings illustrate the intrinsically rhetorical and variable nature of change.