2nd Update! Thanks so much guys for all your great suggestions. I'm also updating my film suggestions below. Per Gosha and Vanina's suggestions, I will also bring Kungfu Hustle and Crossing Hennessy, and we can just decide on the day by a democratic vote about what we feel like watching on the day :)
I am going to suggest the following two comedy HK movies, both starring Sammi Cheng (one with Andy Lau, the second one with Sean Lau Ching Wan). Both are great movies that satirise features of Hong Kong society (e.g. outward obsession with thinness and money and status), but also celebrate the no-nonsense attitudes and the particular blend of streetwise resourcefulness and common decency of many Hongkongers. They also show many great locations of Hong Kong.
"Needing You" 孤男寡女 (2000 - yes I'm cheating a little as it's techically not a 90s movie, but it has so many 90s movies references I feel it should be made an exception)
This film references and satirises many of Andy Lau's past seminal movies that established him as the leading man of the HK silverscreen in the 90s, but even those who don't know much about the movie references would be able to enjoy him playing the typical go-getting Hong Kong exec and Sammi Cheng's turn as the quirky secretary that earnt her her first Best Actress award at the Hong Kong "Oscars". To me, much of the enjoyment of this movie comes from its satirical observations of office life, as well as lampooning the market mentality of many Hongkongers on love and marriage.
This is one of my favourite movies ever! Sammi Cheng teams up with Sean Lau in this horror-comedy. Their great chemistry and accomplished comic timing made this a joy, the dialogue is sharp as a tack (the old lady astrologer's Chinglish is an absolute delight and she's a scene stealer), and the story has a real heart about what it means to survive after a bereavement. And it has many cute puppies!
IMDB synopsis:
A car accident gives a spoiled, troubled young woman the ability to see ghosts, including one of a former classmate.
