My prior cover band always had a set list, but we'd diverge from it if called for. One of the worst mistakes we made on a gig was from sticking to the setlist. For a reason I don't remember, we'd gone off the list and get the crowd dancing doing so. Then we got back on the list, and the next song up was a non-dance tune for which the guitarist changed guitars. In the pause (aka dead space....) a girl in the crowd came up to me and specifically asked us to keep up the dance music. I said, "Let's skip this tune, they want to keep dancing," and the guitarist said, "no, we're playing this one now." Five minutes later we were playing to an empty room.