"I'm so much geniuser than you!"
"In your dreams!"
That day they had Charms and Transfiguration classes, and Harry swiftly found out that while Hermione was very good at Charming things. Harry was not.
Harry was sad, and vowed to make up for it in Transfiguration.
"Transfiguration," said Professor MacGoohan, "is not permanent."
Harry raised his hand. "Why?"
"Nobody knows. Now, class, we'll take an Unbreakable Vow never to transfigure anything in any potentially dangerous way."
Harry abruptly lost all motor control. His face splatted into his desk. He made mrf mrf mrf noises. What he was trying to get across was that if transfiguration was impermanent, transfiguring things in dangerous ways would be the primary purpose of transfiguration, blowing people up through steric mismatch would be The Whole Point. Why would you do anything else?
No one heard his cries; they were taking an Unbreakable Vow. Then they were talking Quidditch and getting debited points for talking Quidditch. He just lay there flatfaced, allowing his tears to merge with the wood of the desktop.
Then he got docked a point for Ravenclaw for not taking his Unbreakable Vow with the rest of the class, and Hermione outTransfigured him and got two points for Ravenclaw, and he went to bed early and cried himself to sleep.
And then he woke up at midnight and realized that he'd failed to rationalize away her superiority and cried himself to sleep again.