Garden of Giants

Why is it that when we're outside, we create spaces that remind us of being inside, and when we're inside we (well, definitely me) create spaces that remind us of the outside?  Outside we make "outdoor living" spaces, treehouses, fun sheds, outdoor kitchens, patios with rugs, etc...  and inside we want our windows wide open to reveal views of the outdoors, and we use natural materials & objects