One of our teachers who was teaching Economics to us was replaced by a young and newbie teacher and whole the class was not satisfied with this change.
The new teacher was not extra ordinary one.I was sitting in canteen and commenting about the bad performance of the new teacher.
Unfortunately the teacher was seated there and I was not aware of the fact and he did obviously listen to all my harsh comments.
I was so ashamed of my act that I, without saying sorry to him, left the room. And it was a second blunder from my side. First I hurt him and second I did not say sorry to him.
i think you do not need to worry, if your teacher was really bad than he deserves to listen all this, and he may try to change his attitude after hearing all this about himself. So cheers