Most of us hate school and college.
For understandable reasons.
We apparently do not learn anything that will be helpful in practical life.

However, school and college teach us an important concept of life: of HOW to learn.

That understanding of how to learn, teaches you to be a student forever, even when you are out of your college, without any teacher.

Which means, if you have to be learning forever, the best thing you can take away from school and college is to learn how to be a student. 

For life.