There's something very frustrating and sad about the way this video concludes. It's not simply the distant lovers just barely missing each other, but a lack of communication and understanding that runs much deeper. At some point in the past, one imagines these two where on the same wavelength - back in their "salad days" of uninhibited expression. But as this video begins they are already miles apart, with the woman looking less than hopeful of things ever working out as she takes a somber photograph in the mirror.
When the man receives the picture it's as if he hasn't thought of her for ages; he is frozen in the post office contemplating what he might send back. He scopes items in the hands of other people looking to mail something that day - from a simple greeting card to a ring on a finger. What he eventually decides is to send himself - what better way to reconnect with his lover?
But in his eager preparation for his visit, he is growing farther and farther away from her. The man is traveling to a place where the woman has been patiently waiting for some time. All she wanted was a phone call or some sign that he cared, because she has come to a decisive point in the relationship where she questions its future prospects. The man is under the impression that his one grand act will sweep her off her feet and make everything as it once was - but he fails to understand the thinking of his lover. It may very well be that the woman does the same in deciding that he has forgotten her (people have different ways of communicating), but she seems more than patient in her waiting - drawing, calling him and checking the mail regularly.
The song poses the question of "maturity" as either a positive or negative ideal. On the one hand impulsive action can lead us into problematic situations, but at the same time suppressing our emotions avoids the truth of the moment. What's sad is that the man acts immediately upon a novel idea which is born out of love, but he also avoids saying outright how he feels about his girlfriend. He puts himself in a box - but he does so for her. There is an effort made to reach her, but she has already lost faith in him. Thus it's not just a single mistake, but a loss of harmony between them that has occurred over time.