If it's not Montessori, you're in a gulag.

Too severe?  As Andrew McAfee, author and former Montessori student, put it in his Harvard Business Review article:

When I got too old for my Montessori school and went to public school in fourth grade, I felt like I'd been sent to the Gulag. 

Fortunately, McAfee survived and gained a deeper understanding of his Montessori roots:

The main thing I learned there is that the world is a really interesting place, and one that should be explored. 

Well, that seems like a fairly noble takeaway for a system that he only experienced through age nine.

Now play a little game in your mind where you imagine that he was able to stay in such an environment until age 18 and then went to college to follow his passions and interests in exploring the interesting world.  Next step: (still keeping your eyes closed, but somehow reading this) imagine that ALL students were in schools that fostered such an outlook.