Tonus - I think the focus on "who lied first" is a distraction (though it might make an interesting Abbott and Costello routine). Even as an allegorical tale, it implies that god withheld important understanding from mankind and left us to our own (uninformed) devices, then punished us for it.
Meanmustard brought up some good points regarding the very possible mental capacity of Adam and Eve at this juncture, which I believe further explains and justifies the simplicity of God's command to stay away from the tree of knowledge.
The command was so simple and elementary so as to borderline on 'dumb'. Why did the snake insist on eating from this forbidden tree given all the circumstances? As mustard pointed out, Adam and Eve couldn't have fathomed the consequences of disobedience, since even the concept of 'death' was not clear to them...such was their lack of comprehension.
Was it really about forbidding them from critical and life giving knowledge? Were they truly going to be a most miserable unhappy couple for being humble and trusting their Creator?
It was the snake that felt what you described or implied tonus.