I've seen hundreds of shows over several decades and only one stands out in my mind as being disappointing...
The Allman Brothers Band on 8/1/93 at Great Woods in Mansfield, MA.
Dickey Betts had been arrested the day of the show and wasn't going to be able to play that night, so the band got Zakk Wylde to take his place at the last minute. He played along reasonably well, but just wasn't a good fit for the band musically or otherwise. It was like a member of Spinal Tap had been inserted into an Allman Brothers show.
He strutted around the stage with his black & White bullseye guitar between his crotch for most of the night, making faces and looking more like a heavy metal cartoon character. At one point he stood on the edge of the stage and stuck the guitar between his legs and started wanking it, while sticking his tongue out at the crowd like he was trying to be Gene Simmons at a Kiss concert.
Two of the three friends I was with, walked out halfway through and I wound up leaving with the other friend before the show was over.
They should have just postponed the show until Dickey got bailed out of jail and was in the mood to play.
And there is another thread on this same topic...
http://www.musicbanter.com/general-m...ever-been.html