Percy often follows his instincts, making impulsive decisions without necessarily thinking through the problem that he faces. At the beginning of the novel, his decision to pursue Dr. Thorn and the di Angelos leads to tension between him and Thalia. The daughter of Zeus blames him for Annabeth’s disappearance, telling him, “If we’d stuck together, we could’ve taken him without the Hunters getting involved. Annabeth might still be here. Did you think of that?” (33). Then, later, he leaves his post defending the demigods’ flag during Capture the Flag, and Thalia blames him again for losing, almost leading to an all-out fight between the two of them.

When Mr. D warns him about how heroes are dangerous, insisting that heroes “take what you want, use whoever you have to, and then betray everyone around you,” Percy begins to think more carefully about his actions (134). He thinks his actions through more, especially after learning about how Hercules used Zoë. In the final battle with Atlas, he realizes the limits of his own abilities and is willing to sacrifice himself by holding up the sky so that Artemis can fight the Atlas.