The physical benefits of yoga are a mere fraction of the true reward of practicing. It does take time (and practice) to "see" or feel the changes emerge. Patience and perseverance will pay off. The practice of yoga will even help you become more patient if that is an issue.
Here is a short clip from my You Tube channel explaining more about a lifestyle of a yogi: http://youtu.be/mwOT7YUSPtc
Enjoy your day and your practice!