This film became so popular, that kids in Hong Kong started wearing long coats, known as "dusters" to copy the lead character in the film.
Upon its release, this went on to become the top-grossing film in Hong Kong film history and held that place for several years.
Chow Yun-Fat wore Alain Delon sunglasses in the movie. After the movie, Hong Kong was sold out of them. Delon sent Chow a personal thank you note.
The character of Mark Gor proved to be so popular that many young HKers adopted his style (black trenchcoat, sunglasses, match in mouth). Stores around HK were sold out of the distinctive Ray-Ban sunglasses in less than a week after the movie premiered. All this led to a blasting of John Woo by critics and government officials that he was glamorizing the Triad lifestyle.
Even though he is now universally known as an action hero, one of the main reasons John Woo wanted to cast Chow Yun-Fat because he didn't look like one.