It makes sense to me why this is...once I was in gear with a heavy workload, I didn't dare stop because it seemed counterproductive to me to do so. Just keep going until I was actually useless. With so much work, stopping just seemed wrong. An as-yet undeserved break.

Not saying it's right...just saying that worker-bee logic tells you to keep going. It's ground into us. If you stop to think about it, you'll go mad...and won't want to go back to work. You'll sit there, feeling the truth of your fatigue. You'll get angry about it...that is, if you still have the energy for feeling anger at that point. "I'll think about this later"

Stupid but true. And "later" seldom comes. If you're lucky, sleep comes.