It does stand out when presented this way, doesn't it? (Although, I'm not sure I say "goodbye" either. When talking to the wife it's usually "love ya," or "home soon." I don't actually talk on the phone much. Dislike it, always have.)
I suspect what filmmakers know is those rote phrases are disruptive to narrative, we're watching the screen and listening for meaning, so watching conversation fizzle out in essentially meaningless formalities would jar the viewer out of the search for meaning by forcing them to pay attention to an element of conversation that is almost unbearably tedious in that context.
Any film school students out there that can confirm my suspicion or have a better explanation?
