it wouldn't be optimized for people who differ in any relevant respect from average.

School is potentially crippling if you're smart. If you're smart, school rewards you for just basically showing up. Don't mistake the ability to get the right answer in class with the ability to accomplish something in life, where there generally aren't right answers, only better ones.

If you listen to the praise, and judge yourself by their false standards, you may manage to make yourself useful to some employer, but you won't make yourself useful to you. You will never learn there the most important thing you need to learn while growing up - how to run yourself.