Feng shui problem: the rented house found a red envelope with a lock of hair between the stickers on the glass door between the room and the kitchen.

Hehe, don't worry about this. It is a way for Cantonese to exorcise evil spirits. It is said that when someone is possessed by evil spirits or bad luck, they cut off a pinch of hair and wrap it in red paper, and hide it in a hidden place in a crack in the wall or door, so that evil things or bad luck can't find themselves, thus achieving the purpose of eliminating disasters and reducing disasters. Of course, this is just a superstitious practice, and it is not clear whether it has any effect.

As for the lock of hair you found, just throw it away. If you believe, you can find a crack somewhere else, and everything will be fine.