The articular cartilage coating the major mammalian joints, such as hips or knees, presents the most efficiently lubricated surfaces known in nature. When this lubrication breaks down, however, the result can be degradation of the articular cartilage, and onset of osteoarthritis (OA). In recent years we have elucidated the molecular origins of the remarkable reduction in friction at the cartilage surface. Our results indicate that it is due to boundary layers in which several components act synergistically, exposing lipids at the slip plane, and I describe how this understanding may lead to novel approaches to alleviate OA.