Colours have a strong impact on our perception of the volume of a room. Of course you won’t push back any walls by painting them white but you’ll give the impression of having more space. White or light walls tend to enlarge the size of a room. Combined with a dark back wall, you’ll increase your field of vision. On the contrary, a light back wall combined with dark side walls give a sense of depth.
Colour is light, and the colour you perceive an object to have will change with the amount and type of light falling on the object. The artificial light you rely on in your home is most likely to be incandescent. This light is yellowish and warm, although a new type of bulb corrects the yellow so colors appear truer and clearer.
If your house is surrounded by trees, the light that enters will have a greenish cast, which can change certain shades of yellow to an unappealing yellow-green in summer. Other colors may not be as affected by the filtering effect, and your eye (and your expectations) will compensate to some extent for any changes.