Day by day, week by week, month by month, year by year, as we grow up, we start to think of other things than just how to get good marks or to impress ourselves with how good or bad we actually are. When we reach adolescence, our feelings start taking attitude, we fall in love, we make many friends with whom we go out and have fun.
In this part of our life, school can not interfere. Although we learn many things in school, it does not teach us how to love. This chapter of our lives is teached and learned by ourselves, and if something goes wrong...well...that is where experience gets involved.
From all the things we are being taught in school, some are let outside for experience to teach us. It is said that experince is the worst teacher of them all in one's life, because, at first it gives you the test, and then it teaches you the lesson. For example, in a relationship, you know what to avoid, but at some point, you make a mistake, and only after you suffer the consequences, you learn that you shouldn't have said or done what you did.
Once we finish school and face real life, we get to realise that what we've learned in theory is much harder to put into practice. We have to make our way through life, and try to avoid hitting the walls that surround us, so that the pursuit of happiness is much easier.
That is why, we learn both through studying and through the experiences that life gives us.