Doing tai chi is like acting out a metaphor for life in general, through slow graceful, effortless movements, emphasizing calm balance and inner poise that flow like a river, at the other end of which you feel refreshed, energized and recharged, ready again to live, love and ride life for all it’s worth. That's when you’re present during practice. Because of course the tendency, even for masters, is for the monkey mind to busy itself with thoughts and worries about past or future or both, even while in the midst of practicing this powerful meditative art.
And though this will still have beneficial effects on the body and energy flow and eventually even on the mind, it certainly doesn’t give you the full hit.
On the other hand, when you surrender fully to the movement and remain focused via the sensations in the body on the present moment, allowing thoughts of past or future or both to subside, you experience such power and recharge factor, it’ll give you all the power you need to handle whatever life throws your way.
And it’s no different in everyday life. All of life is Tai Chi – the name actually means supreme ultimate reality in any case and that includes just about everything. Be present in the moment – allow the past to subside into history where it will resolve itself and the future to remain in the latent state where it will take care of itself – and you’ll be with such power from moment to moment that nothing could stand in your way.