in Kashmir at least, there is a big thing about "Six months later, I still get nervous when I hear an unexpected knock."

this late night knocking has been connected with bad omen because for the past 30 odd years, many homes have gotten bad news of their loved ones being killed or they having disappeared.

that said, if you have to go to a neighbour house, or a friends house, you never just go and knock. people might faint or have a heart attack. instead you call first or just wait till morning.