One of Pony's flaws stems from his youth; because of his lack of life experience, he is unable to see the difficult position his brother Darry is in. The night that Darry hits him, he and Pony are at odds because Pony has come in much later than expected. Darry explains,
I reckon it never occurred to you that your brothers might be worrying their heads off and afraid to call the police because something like that could get you two thrown in a boys' home so quick it'd make your head spin. (Chapter 3)
Darry is more concerned than most brothers because he is also acting as a parent, a role he is unequipped to tackle but one he must do well in order to keep all the brothers together. Throughout the plot, Pony judges Darry harshly and can't see how hard Darry is working to maintain custody of him.
Darry isn't the only one who falls under Pony's scrutiny and comes up short. Though Pony is a detailed narrator, introducing readers to the world of Socs vs Greasers, he also finds fault with pretty much everyone in his own group. Although he understands why the Greasers act the way they do, he still doesn't have much tolerance for Steve or Dally. He is even critical of the girls that the Greases go for:
They were the only kind of girls that would look at us, I thought. Tough, loud girls who wore too much eye makeup and giggled and swore too much. (Chapter 1)
Pony judges his brother, the Socs, his teacher, the girls Greasers date, and members of his friend group. He has pretty tough criticism for nearly everyone.
He nearly fails to see his ticket to a better life: education. Pony is smart, and Darry reminds him of this numerous times, but Pony is so caught up in Greaser survival that he doesn't focus on school. When his English teacher tries to help him at the end of the year, Pony's first response is that he just "can't help it." Everyone around him sees his potential, but Pony almost lets his abilities flounder and produce nothing.
An unforgettable teenage narrator with much to say about the world he's been thrown into, Pony seems to redeem many of his flaws by the novel's end.