I was that kid. When school got more challenging, I spaced out and did worse.
It's a source of frustration for me. I know, and always knew that I had the intellectual acumen to to better, but I never had the self discipline to do so. I tried every day to just buckle down and finish my work, but it is easier said than done.
On the other hand, it was always those mandatory literature classes that hurt me the worst.I always did better in the courses that required more thinking than reading.