We've played a few where we've been kicked off after 1 or 2 songs, normally due to being banned from the venue from previous incidents...
The best one was playing in a local Conservative club. Some punk band asked us to play the "headline" slot. The house PA was some tiny 100W carslboro system, so we turned up with our own 500W PA. Accompanied by 300W of bass, 150W of guitar and a loud drummer, this did not go down well with the regular punters in the other bar and the neighbour who called the police because pictures were falling off the walls We did not get asked back to play again.