Have you ever wondered what people think about when they are "idling", that is when they are waiting for their next event to occur? Examples of "idling" include waiting at the doctor's office, waiting at the bus stop, or sitting in the bus or in a car.
For example, when I'm riding in a car and we're driving past a bus stop, I sometimes think about how the people at the bus stop might be thinking "I wish I was in that car".
When I'm sitting on the bus, I generally look around the bus and speculate about what other people might be thinking about. Although these days most people on the bus just listen to their I-pods, I'm sure they nonetheless at times actually reflect about what's on the minds of other individuals on the bus.