"No, no," Mr. Bruner said. "Oh, confound it all. What I'm trying to say … you're not normal, Percy. That's nothing to be—" (2.67)
Does Percy enjoy being "abnormal" in the beginning (before he knows he's a demi-god)? Why does Chiron wait so long to show Percy his true self? Why is Chiron so flustered here in this moment?
My heart sank. Grover had a summer home. I'd never considered that his family might be as rich as the others at Yancy. (2.94)
Money has never been an issue between Grover and Percy – they've always been able to relate to one another. Percy has always believed they had lots in common. But, here, Percy is realizing that maybe he's different from Grover too. This really makes him feel lonely. He just wants to meet someone like him.
What I didn't tell them was that I'd have to get a summer job walking dogs or selling magazine subscriptions, and spend my free time worrying about where I'd go to school in the fall. (2.74)
Here, Percy points out another way in which he is "different" and doesn't fit in: he doesn't have as much money as most of the kids attending Yancy Academy. Being relatively poor definitely isolates Percy from his school community. And that's on top of the fact that he is also labeled a problem child.
They went back to their conversation as if I'd never existed. (2.76)
For most of Percy's life so far, people don't notice him. In fact, Percy's mom does everything she can to make sure people don't notice him. And she loves him more than anything. Man, being a demi-god is really, really hard.
I started to understand Luke's bitterness and how he seemed to resent his father, Hermes. So, okay, maybe gods had important things to do. But couldn't they call once in a while, or thunder, or something? (8.10)
Being all-powerful and immortal, it seems like it seems plausible that a god might be able to find the time to check in with their demi-god children. What could the gods possibly be busy with? How do the gods feel about their demi-god children?
The attack had scared everybody. It sent two messages: one, that I was the son of the Sea God; and two, monsters would stop at nothing to kill me. They could even invade a camp that had always been considered safe. (9.5)
Percy feels like a menace no matter where he goes. Just when he found a safe place, a place to really call home with kids like him all around, he becomes a threat to that very place. He is a destructive force. He doesn't really know yet that the reason he is a destructive force is that he is really powerful.
Even here in the Underworld, everybody—even monsters—needed a little attention once in awhile. (18.199)
Poor old Cerberus really wants someone to play with him. The Lightning Thief teaches us that being lonely and isolated sucks for mortals, monsters, and gods alike. There is a universal desire among all beings to connect with or interact with others.
But I thought of how few people there were in Elysium, how tiny it was compared to the Fields of Asphodel or even the Fields of Punishment. So few people did good in their lives. It was depressing. (19.14)
Percy seems to comment here that even if you do really good things in your life and make it to Elysium (like heaven), things will be a little lonely there. You won't have as much company as if you hung out on the Fields of Asphodel. Maybe having company doesn't matter to a dead spirit, but it sure matters to a living one.
They protested, and it was hard to let them go after all we'd been through, but I knew I had to do this last part of the quest by myself. (21.9)
Being isolated for so much of his young life helps Percy be a bit independent and helps him recognize when he has to do something on his own, like delivering Zeus's master bolt. It takes great courage to march up to Mount Olympus all alone as a twelve-year-old boy.
Just when I'd started to feel accepted, to feel I'd had a home in cabin eleven and I might be a normal kid—or as normal as you can be when you're a half-blood—I'd been separated out as if I had some rare disease. (9.4)
Percy's seems doomed to living a lonely life. Maybe that's why his mother worked so hard to keep him from realizing that he is a half-blood. The life of a demi-god must be a really lonely one, especially if you are the son of the big three. Are you surprised that Percy isn't more excited about being claimed by Poseidon?