Here is the subtitler’s nightmare:

There was a ritual particular to Hong Kong when I lived there in the 1980s. It was called the Midnight Screening. Hong Kong cinema was flourishing; grand old studios such as Shaw Brothers and upstart production houses such as Cinema City were producing hundreds of new films every year. The new releases always hit the big screens on Thursday night. The Saturday night before, at selected cinemas, audiences were given a midnight sneak preview. The producers, directors, stars and crew all attended, and film fans didn’t think anything of lining up outside the cinemas in the middle of the night to catch a glimpse of their heroes. Neither did they have any qualms about being vocal in their reactions to the film—that was the whole point of the exercise. When they liked something—a line, a gesture, a joke, a plot quirk—they cheered and laughed and hollered their approval. When they didn’t, they groaned and hissed, and at the end of the screening, let out a collective Cantonese obscenity, in which the final phrase lo mo (‘[your] old mother’) was understood: dyooooo. If that happened, the cast and crew would scurry away as fast as possible to see what they could nip, tuck or tweak before the following Thursday.