years ago now, oddly, my then gf, two of her friends, and i were driving in the mountains and they were mutually discussing how their feet and ankles and legs would be sore at the end of the day; they all had jobs that required them to spend much of the day on their feet.
and at the point where they were discussing just how beat they were they either realized there was a fourth person in the car or, more likely, i felt the need to chime in and mention how beat i am mentally.
that is not to say that what i do is more mentally challenging than what they did/do, only that spending a day shuffling between 50 files, connecting information, creating and sourcing spreadsheets, and logically connecting everything will take its toll. you go blind at some point and your head feels filled with cement.
but it's not the same. and the moral of the story is, shutting up is always an acceptable choice. or nearly.