Most of my current knowledge is something that came not from school, but by way of conversations with people or reading books and news articles or on the net.
School education provided me with such good foundation,that building more knowledge on it came naturally. In that way I couldn't have done so well without school. I bet the whole 10 years on it was worth everyday.
Graduation was a revelation of society। While school provided a safe and static environment, college was more of a vibrant and casual place to be. I learned more from outside my classes than inside them. Though attending classes didn't teach much, what it taught was to be independent. In this sense college education was very important, for individual development. I should have put in less number of years and more number of hours in effort.
But, this is a postmortem view of the situation. If I knew what I had to learn in advance, I could have spent less time and effort to gain that knowledge. The point that what interested me and what I had to know was not known to me, is what necessitated the 20-year span. This required me to learn a lot more than required and lot more than what I could actually retain. In this sense the 20 years spent on my education was a necessity and rather insufficient.