Kids lie to avoid eating vegetables... because humans are evolutionary adapted to really like sugar, and they know that higher sugar foods exist.

Sugar = good is no longer an appropriate heuristic given the change in nutritional availability - in fact it is now harmful - so we force kids to behave differently.

It's not clear that school is similar. Is it not the case that people learn better when they are adequately stimulated and engaged? Even if not, how far should we go in making kids miserable to force them to learn more? Do we need to make them miserable or is there an alternative? This is what I mean by asking why, and it's not clear to me what all the answers are (it's a very complex question).