WHY IS GOOD POSTURE SO DIFFICULT TO ACHIEVE?

Our shoulder blades dictate the position of our shoulders and shoulder blades have very few mechanoreceptors (the means by which the brain connects to them). This, therefore, means we don't know what our shoulders are doing.

Combine this with the brains' reluctance to accept us upright (The brain wants us safely down on all fours), generations growing taller, living longer, long hours spent hunched over mobiles and computers plus, tiredness then you begin to see why we ALL have postural issues.