(The child who is going to grow up to be a real pianist truly ENJOYS his/her piano lessons - and that is why he/she does all the scales, etc, with enjoyment [probably because he/she pictures the future skill when it is developed].  The child who is NOT going to become a competent  pianist is bored by or actively hates piano lessons.  (I speak from personal experience, as I was just such a child who hated his piano lessons AND the practice!)