You’ve probably been told at some point in time (or constantly), to alter your posture. Mainly things like stand up straight! or pull your shoulders back! or suck that stomach in!. All of which definitely affect your structure, but alas, have nothing to do with proper posture and, in fact, are detrimental to achieving the natural alignment of the body. Instead of achieving good posture what is occurring by these methods is posturing.
 Posture and posturing, what is best for the body and what you wind up doing with your body, are two very different things. Posture has to do with the proper mechanics of structure while posturing refers to what your emotional self does with your body.
Proper posture is where your body will find itself when it is flexible enough and you are emotionally capable of remaining in your Free Space, that place of ease and comfort which manifests when all posturings cease. This is possible only when the tissue is healthy and there is enough space in your joints to allow alignment to occur.               
To illustrate my point about posturing it is first necessary to observe all the ways a body can distort. (Refer to the essay on the Free Space for a detailed description of proper posture.) Place yourself in the midst of a group of humans and watch them stand and move. You will see that there are thousands of ways in which we as a species pull ourselves out of our natural alignment in order to express our emotions. Nothing wrong with that, other animals also have a complex system of body language.
The problem lies in the fact that these ways of expressing with our bodies often become chronic and habitual, causing very real and solidified distortions and disorganization throughout the soft tissue and the skeleton.
It is when a body cannot move easily out of these physical expressions that pain becomes an unwelcome guest in the body. Turn-out, a ballet move, is a valid movement except when the dancer cannot comfortably stand in any way other than turn-out. As I have worked on many dancers over the years, I can assure you that this is a common occurrence occurring hand in hand with locked knees and an arched lower back. People who turn their feet out inevitably lock their knees while standing, which causes lower back, shoulder, and neck pain, and have an impossible time trying to break that injurious habit without plenty of reorganizing bodywork and a constant awareness to retrain themselves.
  Be forewarned, standing in the Free Space can be a very challenging endeavor. It is a neutral space for the body to be in, but our mind or emotions are rarely neutral.
It can be likened to meditation when one tries to allow a stilling of the mind only to experience a tornado flurry of thoughts. As you experiment with the Free Space (true posture), the thoughts and emotions will give you a thousand posturing  options-- such as putting your hands in your pockets, standing with most of your weight on one leg and your pelvis cocked, chest lifted up and out expressing machismo (or something), shoulders slumped with neck and head forward portraying sadness or depression-- the list of posturings and the negative repercussions which result are endless. It is such a natural reaction to  express our emotions with the body. Again, the danger is not in the spontaneous expressions which emerge but the expressions which are chronic and habitual to the point that it is impossible to express any other than a few.
With the body, function creates form and form either limits or enhances function. If you want to change your body you must change how you move!
Emotional and Physical Flexibility go hand in hand and each affects the other. Physiology creates your state of mind and your chronic state of mind invites and supports physiological posturing.
This is a vicious circle and an easily proved premise. How you stand and move affects how you feel. To illustrate: stand or sit for a few minutes in a slouching manner, breathing shallowly, head hanging with eyes downcast and face frowning or grimacing. I challenge you to experience anything other than a decrease in energy and sad, disconsolate, hopeless thoughts and feelings. Conversely, stand or sit erect, breathing deeply, head held high, eyes wide, looking up into the sky and a smile on your face. Observe the immediate change of energy, emotionally and physically. We all know people who live in places similar to these two extremes of physiology and state. When you pass someone on the street it is usually not too difficult to determine their state of mind by simply observing their body. We read people like this unconsciously many times a day, as we ourselves are read by others. By changing the ways you move and use your body you can effectively change how you are feeling. If you want to feel different, however contrived it may feel at first, simply ACT AS IF, and you will have your foot in the door.

The practice of Flextasy allows you the possibility of seeing your emotionally oriented posturings for what they are. Daily running your body through the range of motions which make up the Flextasy routine make it possible to break out of the vicious circling of negative emotional patterns and chronic holding and movement patterns and replace them with a spontaneous fluidity of movement and emotions which are not dictated by physiological posturings. As your body becomes more loose, flexible, and supple you will notice your emotional flexibility increasing as well. As you work through physical blocks, releasing stagnated energy from the joints and tissue, an increase in your vital energy results. This is one of the effects of an aligned skeleton and decompressed, happy, healthy tissue.
As the joints and hinges of the body become more mobile and the quality of the tissue is normalized, the body naturally finds its place in gravity, no longer struggling against it.
If you find yourself dwelling on negative thoughts or caught in the whirlpool of undesirable emotions, you can use the awareness of the body gained through Flextasy to come to your senses by breathing deeply, shaking the body loose, finding your Free Space and looking once again at your life with a new attitude.  

What your body wants to do and what you do with
your body are usually two very different things
Learn to let your body be!