Why Thou Shalt Never Tick Off Thy Sound Engineer
One of the first things that I learned as a live musician was to be nice to the sound guy, lest you risk inviting his wrath upon you. If you're a PITA, he can turn you off in the mix and you'll be jumping and jamming away, totally unaware that no one can even hear you, or worse he'll record your @ss and blast it out in all of it's glory (or lack thereof.) That's what happened to Courtney Love when she apparently forgot to pay her sound engineer after the gig.
And for a breath of fresh air, here's the same video with the full mix offering the support that Courtney so desperately needs...