Don't get me started ... 
Oh, alright, Coachella, Chicago and New York from last year. No atmosphere whatsoever, bar the song of the same name.
Melbourne Big Day Out, 2002. Watching a lone loon get chucked out for basically doing a v.bad Hooky impression and for shouting out between songs. And this was down the front. In a venue holding 55,000 people. The people around us actually cheered when he got lifted from the front. S c u m.
Worst ever though, Vancouver 2001. Shit venue, shit crowd, shit performance, no ale. And it rained. So much for a fcuking 'dry-gig'. Only plus-point was they came on at 4.30 or something so we could have a decent night in town afterwards.
Worst atmosphere in this country MEN 98 (boy, am I not looking forward to MEN 06!), and worst venue Wembley (seats to contain the fans and a band who were both surely at their ultimate zenith).