I remember going to this place called Boondocks in houston. Its one of those trendy hipster clubs. The DJ was more interested in showing how much he knew about music than developing a dance floor. All of it was this exotic soul music that was almost impossible to dance to. The dance floor was completely empty. I went up to him and was like "dude, play some 80s music, get the crowd dancing, then start showing off." He gave me this 'I'm clearly superior to you' smirk and didn't respond.
Anyways, me and the girl I was with decided to jump start the dance floor regardless. We both started dancing then she went and physically pulled people onto the floor. Once it got going it didn't matter what the music was too much. But that was an example of a bad DJ. I've seen a lot of them at hipster clubs. They never get the dance floor moving, but I'm sure they feel proud of their vast musical superiority.