Apropos of the last two posts: there's lots to muddle over regarding the Dead and Garcia and notions of professionalism and to what degree they exhibited it. Mid-muddling, I remembered Neil Gaiman's advice about what artists (including musicians) need in order to find work, keep a gig, whatever (from his popular "Make Good Art" speech)
People keep working [...] because their work is good, and because they are easy to get along with, and because they deliver the work on time. And you don't even need all three. Two out of three is fine. People will tolerate how unpleasant you are if your work is good and you deliver it on time. They'll forgive the lateness of your work if it's good and if they like you. And you don't have to be as good as others if you're on time and it's always a pleasure to hear from you.
Sometimes the Dead and Garcia maybe had all three. But two out of three usually did the trick.