What’s the difference between a good yoga class and a truly enlightening yoga experience?

When practicing yoga, even when focusing solely on the physical poses, there exists an inextricable link between the mind and body.  The mind must be involved for the body to relax into a challenging pose.  It’s impossible to stay focused on a worry if you are attempting to relax your shoulders.  It won’t work.  Relaxation occurs when the mind redirects from the worry and focuses on (perhaps) an exhale, and only then can the yogi experience a release in the shoulders. Even within the purely physical component of yoga, there exists an inherent mind/body link.  Experiencing this link is the extent of the depth of most modern yoga classes today.