A teacher is not titled as such because they have a credential and stand in front of a class. Talking to or at students does not make a person a teacher; nor does giving tests and distributing grades. It is easy to do these things, but it is not easy to be a teacher. To be a teacher you need to have devotion and knowledge; devotion to your students and to seeing them as individuals who can be taught if only you can find a way, and knowledge that is not only in the subject matter, but also in ways of expressing details and passion.
Everyday is a test to be passed or failed and it is the teacher who is graded and the success and motivation levels of the students that are the curriculum.