I always have a student, or two, that just seems like they are there because Mom and Dad is making them go. I generally find that if I have a one-on-one with these types of students I can get to the core of their problems and find a way to motivate them. They generally just need some type of attention and to see that the instructor is interested in their learning. Occasionally this is not the case, but it generaly gets them enguaged.
