Houses are things. Parents are people. Homes and families, by contrast, are institutions. (Goffman said a "suite of rooms" is an institution.) We know this because they determine "appropriate behaviour". And notice the interesting thing. There is a difference between what you may do in your home and in someone else's. There is a difference between how you treat your parents and your girlfriend's parents. There is a difference between how you treat the sofa in your living room and the sofa in your girlfriend's living room. That's how homes and families work.