the thing i can't stand about the forced encore is the need/expectation to clap and cheer for 5-10 minutes until the band comes back out, even though you know full well they'll be coming back out regardless. it's like a mandatory ritual that isn't always called for.
i forget which show it was, but there was one occasion when the crowd's enthusiasm didn't hold up for the duration of the in-between period. by the time the band came back out, crowd noise had almost completely died out and they were setting up for the encore in relative silence. felt so forced and awkward.