Would you guys mind terribly if I picked your brains?

The kind of experience you're describing is described fairly often in autistic communities. There's a few variations, generally falling into the categories of sensory processing or executive dysfunction issues. The former category would include not experiencing, or noticing that you're experiencing, 'tiredness', even when your body is acting tired in a way that others would notice (e.g. yawning, stretching, body language). The second case involves not being able to stop whatever activity you're engaged in and go to bed, even though you recognize (perhaps briefly, before being drawn back into what you're doing) that you are tired and it would be a good idea. (This isn't quite the same as 'I'll do one more part, and then go to bed' in that it's less conscious and therefore harder to break out of - in many cases it takes a significant effort of will to stop your body from automatically taking the next step in what you're doing, even if you've actually decided not to take that next step.)

I'm curious to find out if those issues are also experienced by people who aren't autistic - perhaps to a lesser degree, or with different explanations than the ones that I mentioned. Do the issues I described sound like what you're experiencing? Are they close, or similar in some interesting way?