Here's where my brain went with this: if humans are "supposed" to drink that much water (according to modern health wisdom), then our hunter-gatherer ancestors—who presumably lived in optimal conditions they were perfectly adapted to—must have produced nearly clear urine most of the time. Have we normalized mild dehydration to the point where we think deep yellow is the default setting for human pee? Medical professionals generally agree that pale yellow urine—not completely clear and not amber—indicates proper hydration for most people.