In the world of dreams the rules of reality do not necessarily apply. Each dream is unique and it's a direct link to the soul and spirit. Psychology provides its own theories on what dreams mean, but so did tradition and the study of dreams for thousands of years before any relevant science had developed.
Dream Meanings - Milk
If you dream that you are drinking milk you will have troubles. If you hold milk and spill it, then you will have a bitter argument with a friend or relative.