This used to bother me as well, but after film school and years as an indie filmmaker and screenwriter, my most recent viewing of the film (tonight, actually) since I was much younger, answered the question in one line, stated numerous times in the movie: “They only see what they want to see.” This brilliantly brief and efficient line of dialogue covers all the bases completely. This indicates that the whole film is like a dream to Bruce Willis (Malcolm) in the way that dreams for us are sort of stream-of-consciousness. He’s not even aware it’s happening. Maybe the only scenes that happen to him are the scenes we see him in during the movie, so the whole dream is really just over an hour long, in linear time, if that’s even the way time works for a ghost (it clearly doesn’t).
Many people who come back from a near death experience, in fact a few thousand people documented, state that there is a life-review. Like what the Christians think is “judgement day”, except it’s really just a judgement-free observation of your life on this earth in a way that allows you to learn from the whole experience and give this knowledge back to the collective consciousness. Whether you believe that or not, that’s how I like to see this film. Like a “final review” to “close unresolved chapters”, or doors, to use a visual from the film. The Catholics call it Purgatory.
I personally don’t believe anyone sticks around as ghosts, but that everyone goes to the same place after death, and that this life is a choice filled with choices, and pain and joy both are for the sake of learning and growth.
That said, it’s a brilliant concept for a film, and likely does have its finger on-the-pulse of something true, deeper, and profound.
I think it’s a masterpiece of a film…although my personal fave is “Unbreakable.”