Just finished "5x2" so can add my two cents. (Not in the excellent critical response as those upthread, just my ideas.)

I did like the film and I have read many of the mixed reviews. Now I want to see "The Swimming Pool" which most reviews say is far superior. 

It seemed the only way to film this movie was backwards to give us the odd "there is hope as the sunsets" spin ending while we know there is no hope for this relationship. It resonates that this is a beginning to a miserable end. They also do not touch in the final scene as they walk in the sea towards the sunset. The future is already written for this couple.

I can see why many dislike these characters but on the surface - wedding scenes, dinner party - they are just ordinary upper middle class people with secrets and silences that are only present as a strong undercurrent. It is a simple tale and not unlike what may be going on down the street in the next house in our own lives. They are perhaps "the perfect couple" that always surprises people when they announce the divorce.

So I liked the movie because it let the viewer do a lot of work thinking about these two people- likable or not. I see them more as vacant lost people unable to share a basic trust and respect for each other or themselves. Although the female seems to be on the verge of waking up and maturing as the film begins. She enters the elevator without turning around but facing the back mirror without raising her eyes to meet her image. (I liked her in "The Color of Lies.) 

The scene that did not work for me was the unlikely American in the woods at the wedding scene. I see the point but it was a bit much. Also the husband hiding from the birth of his son and abandoning his wife. But she accepted it so again we must piece together the stitches that bind these sporatic tales together.

Enough. I am not a film critic or student as many of you. Just rambling my thoughts on this film. I'll go with I liked it but not in the top 10 for 2004. Top 20 yes.