I teach English in Korea. When I arrived four years ago, I can say for certain there were days when the students didn't want to participate in the lesson. I think this is natural- even for some adult students.
In regards to young learners, the spectrum is wide from one student to the next. John is outgoing but craves attention. He may give wrong answers to make his classmates laugh. Jane is shy. She may be terrified of what her peers think of her. The point is, there must be a fun and interesting activity that encompasses all students in a safe environment. By safe, we are talking about a lack of inhibitions and an eagerness to participate meaningfully.
Now, all my classes are taught from computer screens or projectors (3 x 3 meter screens) connected via computers. I use flash files with an abundance of visual imagery. Lesson pace is fast. There is a Q and A game at the end (the last 10-20 minutes) that reviews lesson content. The material engages the students as a group. There are many personalities (albeit developing ones) joined together in an activity that most of them like.
Some students really despise English (for any number of reasons) while others can't get enough of it. I believe this is universal. You can say the same thing about math. I would encourage teachers to find the medium- the material and a comfortable atmosphere where all students have the opportunity to participate. In some cases this is a gargantuan task.
Please see The Language Works profile if you want a link to the flash files I use. Good Luck to all teachers and especially those with difficult students.