"If you want to, and you don't, then that's on you"
Here we can see what Robert Peace though about a person's own determination. People should always strive for more and follow their dreams; if they don't then they cannot complain, because then they did not even try.
"Look, anything you do, if it isn't hard, it isn't doing anything for you. So you're better off not doing it. Use your time somewhere else."
Here, Jeff Hobbs describes Robert Peace's view on life. It should be challenging, it should be hard, it should be difficult. If it is not hard, difficult, challenging, then it wouldn't help you achieve your goals in any way. You should do challenging things and always strive for more.
"Like a bird handled by humans whose flock would not accept it back, Rob now wore the unwashable scent of the Ivy League."
Here you can see how Jeff Hobbs, the author, explained that it can be difficult sometimes to go back to your home. Robert Peace was now an Ivy League graduate, and his life and personality were now different. Sometimes it can be difficult for the ones that knew the old you to accept the one you have become.