Nothing that is worth knowing can be taught

At the peak of my career I stopped, thinking I cannot ask for more. I already have enough. After living a life that I wanted and thought that would make me endlessly happy hidden deep down is the "What if's" inside my head. My life changed, everything changed. I got back to my feet again and realized many things. A human like me cannot be contented with what I have. A human will always look forward on what he is supposed to achieve. Yes, I'm not contented but I'm happy. I'm happy with where I am exactly right now. I always  believe in everything that happened happens for a reason. No matter how I educate myself with all the possible things that I know but still nothing is worth knowing can be taught.