I feel like the main character...(spoile rs)

I am certainly not saying this is the RIGHT interpretation, but it is an alternative to "the whole thing is a dream" theory. By the way, I'm not a mental health professional, so please don't read too much into my musings as far as proper diagnosis is concerned. Then again, I'm betting the author wasn't a psychologist either. I haven't read the book, so I have no idea whether there is any additional explanatory information that would support or refute this concept.

Disclaimers out of the way, try on this view for size:

Marc is a desperately lonely and sad individual, an expatriate living abroad in Hong Kong in a seedy little room by the water. (Possibly after the death of his father... debatable but intriguingly possible.) Every day he commutes from the island to Kowloon and back again, a nameless and ignored figure in a sea of humanity that swarms around him but does not involve him.

His mind has constructed an elaborate fantasy to relieve himself from the intolerable aspects of his existence. He imagines himself living happily in Paris with a beautiful and loving wife, friends who have him over for parties, and an inclusive work environment with people who respect and rely on him.

As we begin the film, his mind has started to have problems maintaining the fantasy for whatever reason. Maybe he finds the stress and conflict of living the fantasy too difficult. Maybe he is self-destructive. Maybe an external influence has intruded upon the illusion. So his fantasy world gradually starts breaking apart in ways that are at first small and subtle, then rapidly accelerate, ripping apart the carefully constructed protective facade he has built up.

Of course the film is shot from his internal mental perspective, so things we see as contradictory and physically impossible are allowable as his brain wars between reality and his illusion. His "wife" suddenly doesn't notice something that is important to him. He overreacts. All the other evidential plot points occur. He senses that he is powerless to avert the oncoming destruction of his world, but still tries to salvage his view as the correct one in fits and starts. That is why you get contradictions such as not using the Bali photos as a direct challenge, or the fortuitous appearance of the uniformed blonde in the photo booth that is never followed up on.

His impassioned statements to his wife that "I don't want to lose you" and "no matter what, I'll always be here" are a part of his recognition that her fantasy love and involvement are so important to him, as he knows that in reality his sad living state is always there, waiting to swallow him.

But his fugue state (if that's the right term) is ripped apart in a slow return to reality. He makes the transition with a fevered imagined flight to Hong Kong from Paris (to self-explain how he is back there... note that we never see the flight or the details of the travel). He finds himself thrust back into his humdrum reality of faceless commuting on the ferry. He gets rid of the cellphone that had been so important as a way to communicate with his fantaasy cast of characters, but which had become a haunting reminder of the "real world" absence of his parents. One of the last attempts to reach out to the fantasy construction is the postcard he writes to his imaginary wife, saying how much he wished she was there and how he only truly sees things through her eyes.

He carries around the coat and the postcard as a reminder of the beautiful existence he has lost. The coat can certainly be real enough, one he bought but cloaked in the fantasy of having been given to him by Agnes, his alter ego and saviour who would encourage him to be more outgoing and noticed. (We even get a glimpse of his frustration that he can't make his fantasy work anymore in her line in the restaurant about "But we did everything right today!")

We see him in the center part of the film back in the day to day grind of his solitary existence. Then one day his brain finds a way to reconstruct the fantasy world with the changes necessary to make it work. It has to cover up the things that fell apart in the last buildup. So Agnes is back, but now they have been together on vacation in his Hong Kong. This time she doesn't approve of the coat that the last fantasy-Agnes liked. And this time she approves of the idea of shaving the moustache and notices it immediately. He is back in the gentle folds of his schizoid mind, with the errors of the last construct wiped clean.

Again, there is the half-realization by Marc of what is going on. He sees his postcard that he wrote to the last incarnation of Agnes and knows that it conflicts with this version. So he hides it and then disposes of it. He goes along with the new fantasy in an almost visible decision to embrace this new creation.

In this light, the entire movie has an internal consistency driven by the desperate machinations of a diseased mind. Because we see it from his own fractured viewpoint, it sometimes feels disconcerting and sometimes seems to jump in discontinuities with character behavior that wouldn't be logical to "normal" people.

I found it engaging, haunting, and bittersweet.