Where is it written that ceilings have to be painted white? There’s no Law of Decorating stating so, but for decades upon decades people have painted their ceilings white.
Is it because paint stores carry specific ceiling paint only in white? Or is it because people think painting a ceiling white makes a room appear taller and/or larger?
Actually, the exact opposite is true. When you have small rooms, using either the same color as you use on your walls or a lighter shade of the wall color will make the room appear larger.