Most disappointing concert /gig you've been to?

Toxic Holocaust were pretty awful when I saw them like 3-4 years ago. They were all so drunk (mainly Joel) that they couldn't play the songs without starting over 2-3 times because they were forgetting the lyrics or what to play. Add a bad sound to that plus maybe 20 people watching the show and you've got a pretty disapointing event.
 
Once I went to a Therion concert once.. It was long ago...
The band was on the stage, then there was a electricity cut... We were pretty much shocked to realize that there wasn't a generator at the concert hall.. I was angry as I paid for the ticket..

And also I am so so so disappointed that, Testament is not performing in my city. I bought the tickets, but then Testament announced that they'll perform in one city only, which is not mine... But I bought the tickets, it is injustice! I'll give the tickets back and will buy Judas Priest instead.. And I'll not go to the other city, neither my friends nor me.....
 
I can't recall any concert that I've been massively disappointed by. I was a bit disappointed that Immolation didn't play more off of Dawn of Possession when I saw them. They didn't even play anything off Failures For Gods! :mad:

I do remember this one black metal show quite a few years ago. It was Thornspawn and Summon. Thornspawn fucking blows and Summon did nothing for me. That might've been the crappiest show I've been to but I didn't have high expectations for it so I can't really say I was disappointed.