Joints in the body are designed for stability and mobility. If you wanted to further classify them you could sort them by design of stability or mobility based on what they are most likely to become deficient in. For example: The knee usually fails in stability prior to mobility and the hip becomes immobile prior to unstable and so on.
The Straighten Up America campaign is one of the more successful efforts to correct bad posture. Its comprised of a series of exercises done daily for a few minutes anytime during the day to balance the muscle of the torso, front to back.