In The Absolutely True Diary of a Part-Time Indian by Sherman Alexie, how does "The power of expectations"(p.180) apply to Junior?

When the story begins, Junior has a conversation with his math teacher, Mr. P. (whom he threw a book at and from whom he was expecting a lecture).  Mr. P. tells Junior that Junior has potential, but in order for him to get anywhere in life, Junior will have to leave the rez.  One of Junior's cartoons clearly shows Junior's dilemma--if he stays on the rez, he is destined to live in poverty but with...

When the story begins, Junior has a conversation with his math teacher, Mr. P. (whom he threw a book at and from whom he was expecting a lecture).  Mr. P. tells Junior that Junior has potential, but in order for him to get anywhere in life, Junior will have to leave the rez.  One of Junior's cartoons clearly shows Junior's dilemma--if he stays on the rez, he is destined to live in poverty but with familiarity; if he leaves the rez, he journeys toward hope but it is unfamiliar.  

As Junior takes that risk, he begins to understand that when someone is given high expectations, he will achieve them, or at least some of them.  Junior was destined to live as his parents, alcoholics who could not do what they had dreamed of, or his sister, a girl who also had potential but was living in her parents' basement.  But when he transferred to Reardan, he began to achieve.  He made friends, he dated a beautiful girl, and he made the varsity basketball team.  It is when he is reflecting about making the team that he states:

I'd always been the lowest Indian on the reservation totem pole—I wasn't expected to be good so I wasn't. But in Reardan, my coach and the other players wanted me to be good. They needed me to be good. They expected me to be good. And so I became good. I wanted to live up to expectations. I guess that's what it comes down to. The power of expectations. And as they expected more of me, I expected more of myself, and it just grew and grew...

This scene is an example of the hope that Junior journeyed toward in his transfer to Reardan.  Mr. P. was right when he told Junior that there was nowhere left for Junior on the rez.