I know how does it feel.. I had a similar experience, or even worse ! I was playing some rock/metal stuff with my band in a club, we had some nice reaction from the audience, but righ after we finished, the DJ came in , played some techno & rap... I was amazed by the reaction he had, every body was dancing on his music... that lucky drum machine bastard !
I was wondering how much time did it took him to learn every thing about the buttons on his machine... a couple of hours?

RAP IS CRAP !