My biggest regret from high school is that I studied a lot at that time but never educated myself. The difference is not as difficult as it seems to understand.
(Courtesy: Association for Psychological Science)
What I mean is I used to be nothing more than a bookworm when I was in high school and all the credit goes to no one but my parents. They had always taught me to give marks the first priority and I followed their instructions blindly.
So I studied and studied and studied taking no regard of anything inside or outside of myself. I was clueless about the changes taking place within me, my growth and also about the things happening around me in the world. This made me a topper, but very very dumb.
When I graduated from high school and faced the world, I realized that there are many other things to be proud about than just marks and grades. And unfortunately I had none of those other things.
I wish I had mingled with friends, learned about the world, and seen everything that I was supposed to see in my teenage years.