Color influences how we feel. It can make us feel energetic or peaceful or happy.
Likewise, it can make you feel warmer or cooler. If you have a room predominantly
featuring a cool color like blue, purple or green, consider adding a warmer hue such as red, orange or yellow. Web MD has a great article on the Psychology of color and how it affects people day to day.

However, you don't have to re-paint the entire room. You can get the desired effect by just painting one accent wall or using warm-colored accessories. Bright throw pillows, vases and rugs can also perk up your mood in the winter. Pick up some flowers at the grocery store for your coffee table or kitchen island--both.