The Purpose of Exhaustion

I am so exhausted...

Exhaustion is such an interesting topic/creation. Exhaustion is also one of the many things that dwells amongst the realm of simple complexities or complex simplicity. What does it truly mean to be exhausted? On the surface, it means to be tired, pooped, weak, fatigued, etc. However, below the surface, the meanings goes a little deeper. On one hand, it could mean that you have truly pushed yourself hard; that you went above and beyond and therefore, you should reward your body with rest. On the other hand, it could mean that you have not been pushing yourself hard enough; and so any little progress or strenuous activity results in the inability to endure.

I am exhausted... this I know. But what hand does my exhaustion stem from? And what about yours???