We all take lots of pictures indoors, and today's handy on-camera flash units make it easy to make good photographs indoors. But for most amateurs, the subject isn't the indoor space itself; instead, it is one or more people-family or friends, perhaps at a party or celebrating a holiday. Or else, a baby, or the family's prized pet.
The room is merely a shell, its appearance is an afterthought at best.
The skill of photographing a room, whether it's in a house or a commercial environment, is one that is practiced principally by professionals who specialize in architectural photography or interior design work. Most people never give much thought to making a room the subject of a photograph. That's a mistake.
Think how many reasons it might be good to have photographs of certain rooms: