And it turns out that it really is important to encourage one's child to practice the piano even though I hated practicing as a kid so much that I even fake-practiced, pressing random keys. It very well may be that, if you'd paid attention, you would have noticed that he'd been overwhelmed by the thought of playing with his thumb, and practicing could have rooted him down so that instead of locking himself in a closet when the teacher rang the doorbell and flat out refusing to come out, he would have rushed toward her.
And it turns out that parents need to be ready to leave for school WELL before it's time so as not to sweep through the living room like a cyclone, roaring for shoes and jackets, and biting everyone's heels on the way to the car. This only makes a child cry all the way to school and appear a mess as he clings to his mother in the doorway of his classroom, desperate to be without the hat he forgot, when really he's a mess because he felt scared of his wild storming mother instead of beloved by her.