Sigur Ros at the big Radiohead South Park gig in Oxford. Awful. I actually walked out well before Radiohead came on because I was so bored by then. Went to the pub.
Oh and REM at Earls Court. They'd double booked with the London Tall Men Convention and I couldn't see or hear a bloody thing. So I went to the pub.
Oh and I walked out of Muse at Wolverhampton Civic. Hadn't had time to get into the second album and got bored because live it just sounded like a wall of noise. Went to the bar.
After these three my mate Andy (present on all three occasions) refused to go to any more gigs with me.