On some level he knows he shouldn't have sent back the jumper. Mother-love made solid, that. But for the five minutes it took there was so much rage in his heart: love drags you down into a mire of kitchen grease and home-made and second-hand, meticulously-patched hand-me-down clothes, never anything new, love enough to choke and stifle and they. Just. Wouldn't. Understand.
Percy knows he's destined for great things. He's young, smart, has energy to spare. He's ashamed of where he comes from. And he believes he's right.
He's read all the biographies. It never took anyone more than that.