Who is a Teacher?

Student: Who is a teacher?

Master: From whom you learn something, though his intention may not be to teach you. He just points out.

Student: Why? 

Master: Because no one can teach you anything, really. Whether you learn or not, it’s your responsibility. Everyone is self-taught - whether one believes it or not.

Student: But there are many who claim to be teachers. How do I know the genuine?

Master: He's not the one trying to sell you an idea and make you feel comfortable - as is in most cases. 
Learning is transformation – which may be painful.

A teacher, sometimes, even makes you feel miserable for you to come out of your cocoon.
If you feel happy in someone's company, if he makes you feel good all the time, he is either your friend or a salesman in disguise.When you can clearly see the fault in your past thoughts and actions, even if you feel uncomfortable in his company, you have found a teacher.