Jon Stewart of The Daily Show cracked a funny one-liner a while back at the expense of Tai Chi. "Chinese men have taken up golf," he observed. "Apparently Tai Chi wasn't easy enough for them."
The joke was funny in spite of itself: the humor was based on a serious misconception of Tai Chi, but it was the very misconception that turned the joke back on itself.
Is Tai Chi too hard? Millions of people practice it worldwide. Many practice it with an
unbelievable intensity, while many others treat it as a light, casual form of relaxed
Exercise. It is what you make of it. In reality the cultivation of Tai Chi is self-cultivation, with infinite possibilities. The result is proportional to the effort.
"The effort" must nonetheless be unattached, or you will be unable to obtain the relaxed, formless nature that is the final goal of the art. Once attained, the result is said to be so profound that one need never practice again to retain the ability.
So students who find it difficult to retain class material must be patient and persevere. It is said that twenty minutes of Tai Chi a day is better than five hours on Saturday: the benefit is cumulative. Keep at it and the reward will come.