I always have this expectation that anyone and everyone has brains. Different amount, and different way of using it, but brains for sure.
In a classroom scenario where a teacher teaches 40 students, there will be a handful that will be the best of the class, and some that will be the runts. Does that mean the teacher is good or bad?
I used to think one way, and then the other. I guess it really depends on the point of view; whether you're the teacher or the student.
I'd probably change the terminology from teacher/student to trainer/trainee to make it more relevant for this post.
There are different learning and teaching styles, and i think that there lies a need for these two styles to match one another before the trainee can get the full benefits. Otherwise, the trainer can be the best trainer in the world and he'll be talking to the Great Wall since the trainees do not get what he's trying to provide them.
So.. given a methodology to train folks, some get it and some don't. Now what's next?