It may sound somewhat strange, but one of the greatest things about the Rolling Stones is that their music doesn't always work. By that I mean that their musical concept, based as it is on the idea of freedom - which for them has always been embodied by an imaginative America, and particularly the sound of its blues, r&b and rock and roll - has a poly-rhythmic, open quality that is unpredictable in terms of results. But this is a good thing: at their best, their multi-faceted rhythms are awesomely compelling, and even when they aren't, the music is still very interesting. They understand that it's possible to over-rehearse rock and roll music, and that one of its most powerful qualities is that some moments will come once and never again. For an example, here is one of their greatest songs - "Gimme Shelter" - which has an intro that has never sounded exactly like the one on the recorded version (from 1969's Let it Bleed), whether played by them or anyone else, a second time: http://www.youtube.com/watch?v=fhBpUJcpiCg&feature=related