After the framework of a structure goes up and the utilities are snugly in place, a building is born. However, we don't live in buildings without finished walls. Not only would it be unsightly to look at, but walls won't last when left unprotected from the elements outside and the regular use of their inhabitants on the inside.
Walls do not exist just to hold up a roof, they also define the spaces we live and work in. Although their primary function is structural, they also provide a very real aesthetic to the architecture we inhabit; an important element in creating positive energy. On the outside, walls need protection from the weather. But a quick tour through any neighborhood or commercial area will reveal the very many different ways to achieve that goal. All siding is not alike. It comes in many different material types, textures, shapes and colors. Like an artist picking which color to use from his palette, a building designer has many options from which to make a unique choice for the public to see. There are also many choices for the inside, or private space. Wallboard or plaster is the most common finish for an interior. It can be textured, painted and even covered with other materials for effect. But a wall must be covered for reasons more than simple aesthetics. When properly sealed, both the exterior siding and interior wallboard become part of the moisture barrier, which keeps things dry inside the wall cavity.
Because they're so common, walls are rarely even noticed. Our brain simply categorizes them as a ordinary sight and dismisses any further investigation or thought. But just because you may not notice them doesn't mean they don't serve an important function in our daily lives. They are the canvass to display our possessions and the shield that protects us from that which we cannot control.