Ultimately, tai chi is not about exercise or self defence. These are by-products.
Instead, tai chi exists to show you that there is a wall in your mind; a wall so familiar and complete that you do not notice its presence.
If you are relaxed and let-go, the wall does not exist.
If you push the wall with your body and mind, it will not yield - tai chi cannot be forced, cajoled, coerced or dismantled by thought.
Only when you yield, will the wall cease to exist.
The wall is your conflict, your resistance, your need to control what cannot be controlled.
Years can be spent in unnecessary frustration, as you seek to will your way through the system - and for all your apparent accomplishments, you will have nothing.
When you can see the barrier in your mind, you have come a long way.
Awareness is the beginning of change.
If you stop pushing and forcing, you will find that you possess energy in abundance.