I just bought a cookbook that has various recipes calling for brown sugar. One recipe wants light brown, another, dark brown. Then, I also need white. I just can't see myself buying three types of sugar.
You can make do with two: dark brown and white. Brown sugar is a funny product, and to appreciate the joke you need to know how sugar is made: After sugar cane is crushed, the impurities in the "juice" are filtered, boiled and skimmed off before the clear liquid is crystallized into white sugar. What is actually being "refined" out of the sugar is blackstrap molasses, a dark liquid that is sweet but also full of other flavors.