Worst Concerts You Have Attended ??

I just left a remark about a favorite band of mine back in the day - April Wine - that I saw in concert and was disappointed. Could have been that it was an off night for them, or maybe they were never good in concert. Maybe the lead guitarist had too much to drink? April Wine was not the worst, however. I remember Neil Young in the 1990's who was on his one-man acoustic show type of tour that many artists were taking advantage of (perhaps for financial reasons) during that time. While a friend of I had near front row seats at Desert Sky Pavilion (now Ak-Chin) in Pheonix, the crowd was just roused up into a frenzy by the warm-up band (James) and here comes Neil and his guitar/harmonica. Wow, what a sonic letdown. I remember getting up and leaving and feeling Neil's glaring eyes on us as we ushered out. I think, to this day, he probably still remembers me. We all can remember the great live concerts we attended, but what were the worst and why?
BTW, RIP Keith Emerson.

In New Orleans, early 80's, was looking forward to Johnny Winter; he injured his fretting hand before the show and played the whole concert with a slide...LOUD x7 .....he clearly adhered to a rigorous regimen of painkiller(s); even at the bar in another room it was deafening.

In contrast, Richard Thompson played a solo acoustic, small-club show in St. Pete, FL in the mid-late 80's; the rather small audience was on the same floor level as him, on folding chairs, and he repeatedly refused to turn up his amplification for guitar or vocals. Us in the back could hardly hear anything....playing or singing...and the last straw was when a bartender drowned him out by crushing an empty bag of potato chips! 
Saw Clapton in El Paso,TX while he was still in the throes of heroin addiction. Muddy Waters opened the show so it wasn't a total washout.
Diana Ross 1999 or 2000 Palace of Auburn Hills. She didn’t know the words and unfortunately her voice had seen better days.
Going way back, The Monkees @ Boston  Garden simply awfull. Hendrix was supposed to open ,but never showed up! Boy did I miss out!
Todd Rundgren in the 70s.  Hands down from this cat . . . . 

No fan.  Girfriend and her bud pleaded with me to get tickets so I did and we went.  45 minutes of mediocre, pompous pop.  45 minutes.  And despite shrieking and applauding of their fans, after 45 minutes and the last couple done by sequencers alone onstage, no encore for them.