I figured it out one day in South Korea. I happened to be in a shopping area at the magic hour. Streets were fairly empty when all of a sudden the doors opened and hundreds of beautiful korean women stepped out onto the street. Apparently they all got off work at the same time.
Oh sure, it's all fun and games until she's comfortable around you. Then you get to experience a kimchee fart. Trust me, the olfactory sensation will wake you from a sound sleep.