Noises all around

It's so funny, the recurring sounds I hear in the building around me as I sit in my apartment. One of my neighbors sneezes really loud; "HA-CHOO!" I know my next door neighbor's ringtone and often hear her giggly "Oh my GOD" discussions. There's also a very strange recurring noise that sounds like a person choking or gagging. I wonder if it's not even a person, if it could be the pipes or something, because if it is a person they either have a chronic gagging condition or they regularly practice autoerotic asphyxiation. Then there's the strange mechanical treadmill-sounding noise that comes on upstairs every morning at about 7:55 and lasts about 5 minutes. It also comes on at other points during the day. Is it a ventilation system or something? All these mysteries! I wonder what kinds of things they hear from me...