Poor posture doesn't only cause aches and pains.  It can inadequate breathing and digestion too.  In fact, your posture has a global effect on every single thing that you do. This is because your posture, your spine and your nervous system are all closely linked. Have a listen to find out how poor posture can trigger your stress response and why simply being told to sit up straight is sometimes impossible.  Especially when that is the only intervention being used to improve your posture.