[TremendousJudge]

My guess is that kids are different than adults. You don't want kids sitting bored in class because it's easy for them. It's awful (speaking from experience here). They either turn inside and do nothing, or disturb the class. You don't want the smart kids to learn less, you want them to learn more

[charlesdm]

Making them work harder for the same grade doesn't mean they still won't be bored, though.