Oh my word! Why are we all putting up with this as a society!? At least half of the people on this board are saying, essentially, 'school is shit for many reasons but you just have to put up with it'! Why!?
Why is it ok to make our children spend years and years of their lives in such an environment!?
It's not as if you can't learn outside of school, or have friends outside of school.
Let's face it, unless you love school, or your parents are not able or willing to spend that time with you themselves and engage with you, etc, then school is just a monumental waste of time...at best. At worst it's downright damaging. 
I agree with Riven - if children genuinely feel that the downsides are worth the upsides and know that they have a choice, that's a whole different situation. But how many children put up with the shit because they think there's no choice. And how many parents, for that matter!
Home education is a real option - it's not impossible, your kids won't have no friends, you won't have to fight them to do workbooks - they'll learn without them. But how many people really know that?
This country (and many others) are really crap in that respect. At least if you hate your work you can change it.