To add to this negativity...
Of the twenty or so Stones concerts I've seen in and around NYC and Philly in the last 35 years, Philadelphia 1981 was by far the worst. But as people have said, even a bad Stones concert is still fun and worth hearing. Wouldn't you like to be able to go back in time if you could... just to say that you heard them play at all, even if you remember they were bad that day. And the day was not a total waste of time for me anyway, because I made a nice drawing:
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By contrast, Philadelphia 1972 was the best concert -- by the Stones or anyone alse -- No drawing from that show.