A medical group by definition is a group of physicians and their support staff who have joined together to practice medicine. However, a medical group is more than that. Medical groups are composed of many different types of subgroups and group dynamics that are in constant flux and which may serve the medical group well or inhibit it from achieving its best performance. Understanding group dynamics is, therefore, one of the paths toward achieving excellence in the practice of low cost but fulfilling medicine. This article describes three types of potentially unsatisfactory group dynamics--homogenized, institutionalized and autocratic. Homogenized dynamics occur when physicians act as though they must all participate in decision making. Managing the group can become deadlocked by one veto. Institutionalized group dynamics lead to an over reliance upon systems and procedures to control work. Flexibility, adaptability and creativity are often lost in the process. Autocratic group dynamics arise when a single individual assumes nearly absolute control of decision making. Each of these group dynamics contain positive and negative outcomes that must be considered when evaluating medical group performance. Case examples and exhibits are provided to operationalize the importance of understanding these potentially dysfunctional group dynamics.