Der Lustmörder (1968)

In a cinema, the projectionist accidentally started showing the main film 'Der Lustmörder' at the beginning of the screening, noticed his mistake, stopped the projector and only then showed the supporting film 'Rendevouz am Morgen'. Moviegoers are now watching this movie and thinking it's 'Der Lustmörder'. A moviegoer gets very annoyed by the tedium of the film, but then finds something else that catches his or her attention.