serious spoilers below
i really loved this film, and i didn't expect to! i always log onto IMDb (while viewing netflix) to see what people think (and to figure out the ending b/c i hate suspense.) :D
i felt like i was in marc's head the whole time. i related to him running to hong kong, and i related to him being on the boat, back and forth, over the water, clearing his head, regaining a sense of balance and normalcy. (if you've ever traveled where you can't communicate the language, you tend to think... A lot... and it can be very soothing.) i loved the way the carrére showed this bit by bit, as marc started going with the flow in the culture he was a guest in, by moving the seat for the lady, getting proper change for the boat, etc.
i loved that when agnés showed up, marc didn't try to argue about anything, he just went with the flow b/c he was so happy to have her back. and in true french film fashion, we get to see agnés as a beguiling woman (doing simple things like brushing her hair and packing) through marc's eyes
i recall, many years ago, a great (male) pal of mine said "the way to make a woman happy is to say 'yes dear!'" now - i don't agree with that per se - but it has it's strong points, believe me - on account of we women can make very little sense to our men at times. i thought (within that concept) it was very brave of marc to shave his mustache at the little hotel. hence, he risked "losing" her again. but he finally puts the past behind him when he tosses the postcard in the water.
going with the flow is something one must do as a tourist, and it's something one must do to effect compromise with one's mate. oddly - it's also something one should do to enjoy this film (judging from the comments.)
this is a gorgeous, gorgeous film. all the tension in Paris is released over the water in hong kong (and glass's score suddenly feels peaceful, as opposed to totally triste.) and vincent lindon's subtlety as marc blows me away.
to me, the key is in what marc wrote on the postcard, and the fact that he threw it in the water (if that makes sense.) that, to me, was the (unexpected) moment i was waiting for as a viewer. i wish i could truly define and dissect this movie as an experience - but i don't have the educational chops for that. all i can write is that i felt an emotional shift at the end, and very light. much like seeing an excellent live show, when the band is in their groove and the audience is right with them. it's a little bit of a give and take, i guess, between carrére and us.