Cold and lack of sunshine make us unhappy, while warm weather and sunshine make us happy. It's really black and white. Where people can walk leisurely, with their kids, dogs, or by themselves, they have time to smile at each other. When it's below freezing, you walk briskly, your body tenses up, and all you can do is aim for the nearest heated place. The human species has successfully populated the entire earth, but evolution has not done away with our need for warmth and light. Our artificial substitutes work, but not enough to make us happy. In fact, this evolutionary shortcoming is particularly strong in people who suffer from Seasonal Affective Disorder (SAD). This video is dedicated to SAD sufferers as well as those who experience milder symptoms of this illness. For them, it is black and white.