They just don't know any better.

We live in a little house--880 square feet. Two bedrooms, obviously one bath. We have neither an automatic dishwasher nor central air conditioning. We have neither a basement nor a garage, and our attic is suitable for storage and nothing else. We get by with two window air conditioners: one for the living room (decorated in Early Fisher Price) and kitchen, the other for the parents' bedroom.
These are the circumstances you must keep in mind when we start talking about the heat wave of the past week. Upper 90's to 100 for highs, with comparable humidity. It started on Sunday, I think, and finally broke on Thursday.
Did you notice which room is not covered by air conditioning? Yes, that would be the kids' room. They sleep on our floor when the heat gets bad.
So, for four days a quarter of our already-small house was off-limits. It was used for diaper changes. Their clothes would be retrieved and the door would be closed. Walking in there was like walking outside, but with less air movement (despite the window fan).
In heat that bad, playing outside was done on a kitchen timer, either early in the morning or in the last half hour before bathtime. I would hang laundry in five-minute bursts, hoping against hope that there was less water in the air than in the clothes. Even the shade provided by our neighbor's tree didn't help.

On top of that, my mother's house doesn't have air conditioning either, so she was staying on our couch. Yeah.

Imagine it. Six people, one bathroom, 780 square feet. Five of said six sleeping in the same room (none snore). Three of said six five or younger.

You would think it would be Tension-and-Fight Central, but it wasn't. The kids were thrilled to sleep in Mama and Daddy's room, like a campout. Grandma is almost a celebrity; having her for a sleepover is a treat. No tantrums, no troubles, no squabbles over which spot was whose.

Thursday morning came; Grandma left and we went to a playdate. That afternoon, I was able to lay Rachel down in her crib when we got back. The other two played contentedly in the living room with Matchbox and Bob the Builder vehicles.

All of which makes me wonder. If we had 2000 square feet, a garage, a basement, two and a half baths, and central air, would my kids get along as well as they do?