Why should I add spices to my food?

Your taste-buds. You don't have to add anything if you don't want to. Often spices add flavors to your foods and people want to taste different things. Some makes food smell good which can enhance appetite. For the most part, adding spices don't really add much health values to your foods, they just add flavors and make food less boring to consume--good food = a pleasure of life! Good luck.