"The evening before my final I got so frustrated, I threw the Cambridge Guide to Greek Mythology across my dorm room" (pg. 18) This is him getting frustrated at himself.
Ch. 8 CHARACTER VS. SOCIETY
"I don't remember touching her, but the next thing I knew, Nancy was sitting on her butt in the fountain screaming, 'Percy pushed me!'" (pg. 9) This is when Percy accidentally pushed Nancy Bobofit into the fountain.
Ch. 1 CHARACTER VS. CHARACTER
"Outside, it was really storming, the kind of storms that cracks trees and blows down houses" (pg. 41) This shows that the characters will face a storm in a little bit.
Ch. 4 CHARACTER VS. CHARACTER
"On the other side of the creek, the underbrush exploded. Five Ares warriors came yelling and screaming out of the dark." (pg. 120) This was when the majority of the Ares cabin attacked him.
"Absolute terror ran through my body. I did the only thing that came natural: I swung my sword" (pg. 13) This was when Percy killed the Fury.
"'Raaaarrrrr!' the monster turned toward me, shaking his meaty fists" (pg.54) This was when Percy was getting almost attacking by the minotaur.