Make sure you check what the item looks like from the back e.g. design of the back of the sofa, or if a sideboard/shelving unit how the back is finished to ensure it has the same quality of finish as the front. If you want to position shelves in the centre of a room, perhaps to act as a room divider, consider a design which has open shelving. This way it can be used from both sides, will not be too intrusive and will allow light in. If you would like to have some furniture against the back of your sofa e.g. a shelving unit/console, ensure the piece of furniture is lower than the sofa height.