I just watched this again and was laughing so hard at certain parts that I was crying. Private Eyes is not the first of the Hui brothers comedies. They began with a variety show that mimicked the highly popular Laugh In on NBC between the late 60s and early 70s. Both the Hui brothers were educated in English-language schools in Hong Kong and no doubt were highly influenced by western cultures. Sam, by the way, was the lead singer of a local rock band and wrote many of the songs on their movies. Through their work, they also pioneered a new musical trend in Hong Kong that combines western popular music and Chinese lyrics. In their TV shows and movies, you can clearly see the same western influences with a Chinese twist. Other than the much more easily understood slapstick in this movie, parts play on linguistic twists and references to the temper of the times. If you are not familiar with the 70s or do not speak Cantonese, you will miss some of the humor. I've turned on the English subtitle while watching this movie and it is nowhere as funny as it is in Cantonese. Even in traditional Chinese subtitle, something is lost as the Cantonese vernacular dialogue cannot be fully translated into the very formal traditional writing.