Messy, I'm intrigued to learn that your reply concerned events in a bus station, and that's because I was set to have "bus station" be my own answer.
I remember a few occasions when I spent time in a grimy bus station not intending to buy a ticket, board a bus, or go anywhere myself, but just waiting on a friend who was the actual traveler. A panorama of people from all backgrounds will pass before your eyes then, one after another, while you're basically just sitting there, feeling like some kind of eavesdropper or interloper.