In my high school we used to take lessons as groups, so the students could discuss the subject and ask the teachers questions about it. We used to have two teachers for one class. We knew one of our biology teachers is very dumb, So we used to ask the other one which was so strict and won't give a clear answer. But we kept asking him for hints because the dumb theacher isn't helpful at all. We noticed that she would walk very slowly toward the group when we try to ask her hoping the other teacher get to us before her. When she tried to prepare a lesson once, the other teacher didn't show up for the class because her lesson was a severe disaster. We also treied to ask her once about polymers and monomers inside the human body. I don't remember what the question was, but I remember she told us that "a ploymer is a chemical compound", and she left. We loooked at her shockingly not nowing WTF she had said. After a month we knew that she used to teach at medical schools. She used to teach DOCTORS in their first year. I have been questioning how she get those jobs since I knew that, and I didn't trust in our education system anymore.