The DJ mix is always a question of identity: Who is the DJ? And what are they trying to prove? Not that they're all so self-conscious, but the mix always asserts something. On The Block is Hot, Pt 2 Blockhead asserted his indvidualism over moody samples from Everlast and Rakim. On Bumps Controller 7 illustrated a knowing reverence for the Golden Age, smooshing De La against Nas and making both sound newly relevant. I've heard James Murphy treat a DJ mix as a sketchbook, Greg Gillis treat it as a urinal, Primo as another excuse to scratch a bunch. I've heard DJ Shadow do pretty much everything a two-armed human can do on a DJ mix. He was clearly proving something.