Well, initial flight training isn't really teaching you how to fly. It is more like teaching you how NOT to kill yourself!
After you are past the "hazardous to your health" stage, you learn the finer points of flying.
Being a life long learner as well as a teacher, I have discovered a few things about the learning process.
Yah, I guess I am professional in this area.
Basically, you don't know what you don't know. If the consequence of a failing grade is grave (ie. DEATH) there are no second lessons!
There is then no way of discovering the things you don't know in a safe manner on your own!
THIS is what makes teaching yourself to fly totally absurd.

CJ