If you want to talk true lessons though. I learned , and I have known for years but have not always done it when I should, the importance of cutting and retying often when fishing heavy cover. Believe me, a BIG fish, probably 5 pounds, which would have won big bass in my last tourney, breaking your line will teach you real quick.
Actually, it wasn't teaching that I needed. It was reinforcement of that teaching, a spanking if you will! ;D That particular bass sho' nuff did that! :'(