> And it only works because it's real: they really do love each other.

Oh Kelly absolutely does love Chuck so it still all fits. Kelly is in pain with pre-crash Chuck's behaviour because she loves him. As adults we learn that love isn't enough for a relationship to work. The theme isn't simply loss but loss of what we have taken for granted. The reason behind the workaholism and the struggling relationship is to establish how he is taking for granted what he loves most.

Some movies just diverge from the themes of the shopped script wholesale but more often scripts state themes explicitly that are treated more subtly in the final movie. The screenwriter communicates by direct dialogue what the final movie shows through performances and direction. Lines that are too on the nose don't make the final cut - directors like ambiguity that tickle a viewer's brain and add depth instead of saying it out loud. They want to puzzle and provoke a viewer.

In the script the message of the story is spelled out explicitly, Chuck's island experience changes him such that he promises to live life better and not be so whipped up in work that he takes people for granted (Kelly). In the movie, there is no grand speech from Chuck about a new enlightened spirit. We can see he is a changed man but it's left up to us to try and understand how. The movie doesn't just paint the message on a sail like the script lol but gives scope for us to find our own meanings.

For me, it's pretty clear it's a similar message as the script. Chuck was living in a self-absorbed bubble and wasn't really connecting with anyone but this bubble is thoroughly popped by his experiences. One particularly nice contrast is how pre-crash Chuck's ebullient ChuckMode attitude misfires with his colleague about his cancer stricken wife (and he doesn't see it) but post-crash, he is more empathetic and connects. The whole Wilson relationship was about the need for connection. The ending is playful mix of Chuck still doing the work (delivering a fedex package) but after he realises who the package is for, stood in the crossroads, I feel confident Chuck is not going to strap on the beeper and chase delivery times again but will now pursue connection.