Artificial lighting thrown onto the surfaces of a room from different heights and angles it can really changes it apparent dimension. The lighting should be unnoticed that way it will set the right mood.
Some people may have a traditional central pendant as the main source of light in their sitting room. This can be harsh, by combining table lamps and other sources of lighting, a totally different atmosphere can be achieved.
Good lighting design means flexibility. You can change your world at the flick of the switch from a bright, functional space to an intimate area.
Lighten up your life. The more individual the source of lighting, the richer the mood.