I've made the effort to watch Chungking Express three times now because I know amongst the more cerebral type of film buff this is rated highly-it's certainly stylish, influenced by the French New Wave, specifically Godard. The first story had me griped but mid-way it cuts to a different romantic story that to be bluntly honest and at the risk of making me look like one of those ignoramuses who write bad reviews on Amazon, was frankly boring. I think the film critic Roger Ebert makes a very valid point here:
"If you are attentive to the style, if you think about what Wong is doing, Chungking Express works. If you're trying to follow the plot, you may feel frustrated...When Godard was hot, in the 1960s and early 1970s, there was an audience for this style, but in those days, there were still film societies and repertory theaters to build and nourish such audiences. Many of today's younger filmgoers, fed only by the narrow selections at video stores, are not as curious or knowledgeable and may simply be puzzled by Chungking Express instead of challenged. It needs to be said, in any event, that a film like this is largely a cerebral experience: You enjoy it because of what you know about film, not because of what it knows about life."
For more info see the Wiki entry here