Shelter to me has to do with being with someone I love. Whether that be my family, my best friend, or my boyfriend.
I've lived in 9 different places since moving to Minneapolis. A few of my favorites were Nicollet Island, 2009 Upton Avenue, and where I live now, a high-rise building downtown on Grant Street. These places were my favorite for two reasons actually - they were with people I love, mentioned above, and they were beautifully furnished and kept clean.
So I would say that most important is love. Second comes the way the house is kept.
Nicollet Island Minneapolis
Upton Avenue House
The View from my Balcony
So my priorities, I've realized, are to be somewhere that is clean and beautiful with someone I love. This might stem from being homeschooled for elementary school. My home life has come to mean very much to me. Especially after living in some not so beautiful, not so clean places during college.
Best Case Scenario: If these basic needs, cleanliness and care for aesthetic, were everyone's priority, I'm not sure much would change. I think people would get rid of a lot of "junk" to accomplish this though - living with less clutter would probably change people's lives. It changed mine. Careful and selective decoration, and reducing personal belongings by at least half is something everyone should do. Living with less is something to be proud of. Running a tight ship when it comes to dishes, laundry, chores, etc is not as easy as it sounds!
Worst Case: I think we've all seen slums and unkept homes, imagine those places were eliminated from earth. Now imagine that there is a strict segregation between clean areas and slums. If there is one extreme, (extreme clean and love) then the other extreme exists (filth and broken homes). Maybe some people go to live underground, and that is a place that is ok not to decorate, or live by yourself. Or a colony of rebels, like crust punks of the future.