TV Quote from The Simpsons 08x25: The Secret War of Lisa Simpson

Lisa: It's not my nature to complain, but so far today we've had three movies, two filmstrips, and an hour and a half of magazine time. I just don't feel challenged.
Principal Skinner: Of course we could make things more challenging, Lisa, but then the stupider students would be in here complaining, furrowing their brows in a vain attempt to understand the situation.