Due to some personal work, I have had a chance to take the metro almost every second day. A couple of observations:
1. A vast majority of the travellers are females. Understandably so, because they belong to the same economic strata where the males travel in scooters/bikes and small cars. But the sheer number does strike you (and you don't really mind).
2. The quietness in the station and within the trains. I mean, even people travelling together are not talking too much. Maybe, because the general ambience (the cleanliness and order) is too unnatural (otherworldly?), too forbidding to make people comfortable talking.