Schools are a way for parents to send their kids to a reliable daycare service. At a certain level, some don't really learn anything there. I did as much as I did (college) to pass among the clueless as normal but wish I had more opportunities to avoid it altogether.
I dropped out after my sophomore year - I had recently moved to the States from Europe, and school was teaching things that I had learned already been taught a few years prior to that. I was completely bored and decided I was done with school. Getting my GED was really easy, and from there I have had a great career - while it may have hurt me in the beginning, I now have 20 years of relevant work experience behind me, it's generally not a concern to myself or any of my past employers - and if I were to interview somewhere that took issue with it, it's probably not somewhere I would want to work.
(fwiw i say this as a college dropout who doesnt regret it at all)