I liked the fact that the older waitress was taking care of her old steady customer. Then I had a thought that was odd, though not unpleasant: I realized I could just as easily not have witnessed this scene, if I had chosen to stay in the bus station. I could have been sitting across the parking lot in the waiting room while this scene was taking place. It would still have taken place. I had never before thought so clearly about all the scenes that took place when I wasn't there to witness them. And then, I had a stranger and less pleasant thought: not only was I not necessary to those scenes, and not necessary to those lives that continued to go on without me, but in fact, I was not necessary at all. I didn't have to exist.
I hope you understand how that is related.