Your Body.

 You don't always have to have the most productive day. Sometimes, your body will demand rest, sometimes your mind will demand it, sometimes your soul will demand it and believe it or not, you have to listen to them. They make you, you can't over work them, you can't abuse them, you can't insult them and you surely can't compare them to others'. They are unique, they are for you and you alone and you must protect them at all costs. You must do what you otherwise wouldn't consider doing. If taking rest is out of the box for you but your mind, body and soul demand a break, give it to them. They will appreciate it, very much so, and before you know it, your productivity will get boosted too. By a huge margin, to such an extent that you will instantly see the difference. Your body is no machine, you can't overwork it, undervalue it and try to abuse it. If and when it crumbles, you crumble with it. Give it the respect it deserves and you'll get back, multifold. 

Love, peace.