I don't know which is more tiresome, 3-4 hours of focused programming and thinking, or 8 hours attending two children below 5.
They are both tiring, but differently. Intensive programming is like working hard at the gym. Tiring, but content. Attending children is low intensity in attention, but constantly vigilant. And you are expected to pay that kind of attention for another maybe 4 years. Very different kind of tiring indeed, both makes you unable to focus afterwards. So while thinking hard makes us tired, not thinking hard can also makes us tired.
They are both tiring, but differently. Intensive programming is like working hard at the gym. Tiring, but content. Attending children is low intensity in attention, but constantly vigilant. And you are expected to pay that kind of attention for another maybe 4 years. Very different kind of tiring indeed, both makes you unable to focus afterwards. So while thinking hard makes us tired, not thinking hard can also makes us tired.