I'm thinking I've been to over 600 concerts in my life, and about 70 of those were The Grateful Dead.
I actually view them as a jazz band. Their music is complicated and cannot be categorized. Recordings and/or videos do not do them justice. It's somehow different seeing them live. Never before have I witnessed hundreds of people break out in spontaneous applause and screams of joy AFTER their concerts, as well as during. Back in the day, a good show could leave you kind of in shock for a few hours over what you just heard. Then again, they bore the hell out of some people. They were one of those bands you had to really LISTEN to in order to understand. Rock promoter Bill Graham had a saying "They are not the best at what they do, they are the only ones who do what they do".
I was sometimes lucky enough to get the same feelings from unknown performers playing in a bar as well. I think when listening to music you have to, as I call it, "put your ears on".
Never saw a fight or argument at a Dead show...not even once. And contrary to a widely held believe, most attendees were not stoned off their face or tripping at the shows.