And Then I Found Out How Hard It Is To Really Change

As you can find evident at any time, Percy blames himself. And he blames himself for a lot. Although a mass amounts of it he can usually move on from.
But never Bianca. He can never forget the way Nico looked at him from that first day they met to after that quest and even now.
He hates him, everyone knows that. Nico hates Percy and the younger demigods crush on Annabeth never seemed to help.
Driven up the wall to insanity, just to find out he was wrong.