This film is not about depression.

Well ok, you can say it is. But I like to think that it's about something Slavoj Zizek talks about many times : The injunction to enjoy. Each person is supposed to "Live life to the fullest" and to "Believe he can fly" all the time. So when at the very beginning of the film when the couple keeps on kissing each other, when everyone is saying "I want you to be happy", when Michael gives Justine that photo of the apple orchard, when over and over again everyone wants to ensure that they have a good time this theme is clear. It is exactly that same thing Claire proposes to Justine near the end of the film : "To sit on the terrace tasting wine when it happens". This is why Justine replies coldly "I think your plan is *beep* She is the only person in the film who tries to defy this order to enjoy, to have fun. Even at the very end, she has her back to Melancholia when it crashes into earth while Claire still cannot rid herself of looking at it - enjoying it. Watch : http://www.youtube.com/watch?v=yaoC1Ts9-VE