Here in Chiang Mai there are free classes/groups at the 3 Kings Monument as well as Tha Phae Gate -- they start at 5:45am! I have been meaning to get there for months now... I'm an early bird, but to get up, out and there by 5:45 is a commitment to be sure.
The meditative aspect slows the breathing down and thereby slows the mind down. This helps to keep the mind clear and less distracted, focused and less inclined to be aggitated. The stretching and graceful movements help us not only to keep supple, but also helps with our sense of balance as we age. Since we feel more sure footed, we are less inclined to fall or slip, breaking any bones in our body.
All of this is to create a sense of well being and presence, and like others have mentioned, not a sense of doing or accomplishment, but rather of BEing.
It's low impact, one needs no equipment, we make no noise, and we need very little room. Once learned, it costs no money and the benefits are many.
Hope you give it another try, Orchidflower! You really can't lose...
Akaisha
Author, The Adventurer's Guide to Early Retirement