What does it mean to be a teacher? How did we learn to be teachers, and why are certain things expected of us?

[:en]Deep down, all teachers are taught the idea of “teachering” from a young age.  I used to play school at home, and it usually involved setting up a teacher desk, writing on chalkboards, pointing at things with yardsticks, and grading papers.  But is that what a teacher actually does or, more importantly, SHOULD do?[:]