Department of Irrefutable Truths: The Grateful Dead Were at Their Best in 1972

Over the past two days I have listened a number of times to the performance of the "China Cat Sunflower--Know You Rider" medley from the Grateful Dead's Europe 72 live performance album.
Those numbers recorded the Dead at the height of their ensemble artistry, and in my humble but infallable opinion rank among the best rock and roll concert performances of all time.  More than 40 years later, I still marvel at their virtuosity.