Let me tell you what exhausts us. It’s not what we do and then we get so physically tired. That can make us fatigued alright, but not as much as what I’m about to tell you.
What exhausts us is the thought of what we are yet to do. Imagine when you have a project at work or a term paper at school. You could stay up until 2 am and do all you can, but because you know the magnitude of what is yet to be done, you feel even worse. From the tiredness that you have from working, but even more, from what you know you are yet to do.