No. It's just hard to believe all people don't get more tired as the day goes on. In fact, eventually, as the day goes on we all get so tired we eventually fall asleep (all of us).
So the nuance is what's your tipping point where you are performing worse due to fatigue.
I start the day tired and wake up gradually until around supper. Then, I eat and do the chores. At around 9pm, I'm fully awake.
When I was a kid, my parents made me go to bed around 9pm. I used to get up every half hour saying "mom, dad, I can't sleep". They figured out quickly enough that sending me to bed early was a waste of time since I would spend 3 hours sitting or laying in my bed waiting, fully awake, feeling like going playing outside.
So the nuance is what's your tipping point where you are performing worse due to fatigue.