A fitted sheet covers your mattress and your mattress pad (if you’re using one), providing a soft surface to lie on. Fitted sheets have deep corner pockets, adding a little extra wiggle room in the case of thicker mattresses. On the other hand, a flat sheet is a fundamental piece of any bedding set, serving as the first layer of the bed that you can actually use to cover yourself as you sleep. You should choose your sheet set fabric based on temperature—cotton and linen are warm, yet lightweight and ideal for the Indian climate.