They may not have been entirely receptive as students. Teachers need to be open to questions they can't answer - this is what causes many insecure teachers to avoid discovery. You need to be that type of teacher. I'm not sure where you observed teachers or where you had your education, but don't give up. The AHA moments are worth all the effort.
Teaching is so rewarding and so much fun because it is so unpredictable.
I hope I haven't gone on too long.