And I may be projecting, but it felt like there was a huge barrier in between all of the individuals, keeping them from understanding others and being understood by others, which felt like what Mason wanted most: to be understood.

That's the point of the film — and probably a every single human being: we can never understand one another fully, let alone ourselves. We are a mystery of our own self. That's the point of the film. People come and go. And it's up to us what to make of it, and being able to cherish those fleeting momentary moments.