Krabapple was having a bad day
and to feel better decides to start failing Max. Maximillian's
always gotten straight A's, and he doesn't understand why his
hard work is turning out to be a failure now. Being the innocent
child that he is, he believes Mrs. Krabapple when she tells him
that he's not smart and that's why he's failing and that all his
answers were wrong.
This is really sad, and most
of us at one time or another have probably had a teacher like
this that was out to get us. They'd always give some lame excuse
for whatever they were doing.