School

It's not what we're teaching kids but how we're teaching kids. I say teach to the extent of the speed the child can learn, therefor let them decide their own speed and direction. Start listening to kids. They know what they're good at and what they need help with and what they like or dislike about their teacher.
But never put a kid into special education when they have no learning disability other than maybe very extreme mental handicap, because my dad worked with perfectly normal people only labeled as "special ed" that now can't do math because they were only not taught it as a kid, even though that wasn't their disability.
If you ever teach less than they can learn then you are denying them of there own true potential, stunting their intellectual growth process, and denying them knowledge, and all future benefits of that youthfully acquired knowledge.