Reds stimulate our nervous system and increase assertiveness. Paint the bedroom red. Chances are you will bolt out of bed. Like reds, orange hues are stimulating. Both color families tend to increase the appetite, which is why they are so often used in restaurant interiors.
People also laugh more and are more gregarious in the presence of orange.
Dinner parties will last longer and seem more interesting in a coral or light orange dining room. Yellows remind us of sunshine. Used in a small room, yellow seems to visually expand the space. Although it may seem like a happy color, yellow can increase irritability. Avoid painting an entire room bright yellow.