Focusing on physical mobility for an hour can wipe you off the face of the planet. Slow movements that engage all the small and commonly overlooked muscles can send you into this strange place where fatigue is spread even throughout the body, from head to toe. In contrast, a specialist workout that focuses on a certain part or area of the body creates a sharper fatigue that you can feel in those specific muscles and those supporting them. The fatigue builds and fades noticeably. This physical mobility and stretching business, it gets you when you're out grocery shopping or doing chores. It feels like it's in your cells and your fibers. It's unique. It feels like a worthy goal has been met, without vanity or excess. Yoga must be just vicious. What's the bigger theme here? Exercise is practice and its effects are maximized when time (as in duration) is largely ignored. Tempo, speed, and form of movement are important, but overall time should generally be ignored. Perhaps the greatest difficulty here is slowing down your mind and focusing the psyche on the condition of the body. Superb skill to build, for all areas of life.
The gods of entertainment can get quite angry and petty when we ignore them. Praise them nonetheless.