Back when i was working with kids and mine were younger, and my sister was working a corporate life, which she still is, we had a debate about which attribute fades most when your tired. For me, it was my patience. For her, it was her intellect. We came to the conclusion that it was probably a universal loss of skill and readiness, and I can now attest the truth to that. I am now working mostly in an intellectual capacity, and it was definitely lacking today. Definitely. Now I was also slow and dropped things a lot, and tended to sit if given the option, but where I noticed it most was in my metal speed, or rather my mental numbness.
So what do you think? What do you lose when your too tired? Does it tie into what is called on most in your day?