The title: a friend just vagueposted it on Facebook, attributed to Patton Oswalt. I should know who Patton Oswalt is, but I don't, actually. I don't know precisely why my friend posted it but I have an idea. The idea below is not it.
The difference between "you couldn't manage to do the assigned etude" and "you're having trouble with the assigned etude; let's figure it out and fix it": this is the difference between a good lesson and a bad one, a good attitude about lessons or a bad one. How I would love to walk into a lesson and feel like I deserved to be there, like I could really play my instrument (or was well on the way, anyhow). What makes a good student? The ability to listen, to differentiate between what you hear and what you want to hear? I have that, to some extent. And then you try different things until you get the sound you want to hear? That, I don't have - not nearly often enough, anyhow. Some (most? all?) kids just do stuff without thinking; they "get it", they are the talented ones, they don't need to read extra books and do extra drills and walk around the neighborhood flexing their wrists or waving a stick like moving a bow. They don't sweat about walking into yet another lesson unable to perform a little children's etude. They just Get It.