What I don't like is when bands cover songs of other bands on their concerts. Like I am here to hear your songs, not the songs of other bands! lol i think the only time i'd contest that is if its a cover track they've gotten a lot of recognition for. eg Disturbed and Shout 2000, Land of Confusion, Sound of Silence. i'd be pretty disappointed going to a disturbed gig and not hearing sound of silence, their version is just so fantastic.