This is so short and late that I'm ashamed of publishing it. I couldn't think of anything for this theme! I know it's a bit rushed, but, as always, I felt like I should post something.
It's very easy to judge, especially when one doesn't know the whole story behind a person's action. It's easy to say the Olympians are damn related, therefore, they don't stab each other's backs because they stick together like a family. It's simple to convince yourself he's your father; what could he ever do to harm you?
That frustrated Luke immensely. Those newbies, the ones who hadn't died on their way, how dare some of them act like the gods weren't the worst thing that had ever happened to them? Of course, most demigods knew better than to expect parental compassion from above, but it seemed they missed the point that they were there at camp, burning the best part of their food to someone who hadn't done a thing for them, apart from ruining their lives.
And all the time Luke kept that in mind. Percy completely missed the point, and had dragged Annabeth with him to the gods' side. He, as a son of one of the Big Three, should understand how screwed up his life was. Annabeth, of all people, should understand his point of view; but maybe she'd been too young. If only Thalia hadn't been turned into a tree by her own father…
In all honesty, what had Hermes done for him? What had he done for Luke's mother? She had been even more screwed up, driven crazy by gods know what Hermes had showed her or said to her. Gods thought they could barge in someone's life, sweet talk mortals into having sex, leave the child to them and disappear, killing two birds with one stone. And never come back.
Or do come back. And ruin things a little bit more.
So, Hermes loved him. So he cared about him. So he knew something in Luke's future, something bad. So he couldn't speak a word of it, couldn't help in any way. Yeah, Luke could feel the love. And that god dared call himself his father.
The demigods who had stayed at Camp Half-Blood; how could they not see? They would always be pawns of the gods if things stayed the same. And the sad thing, the gods didn't even care, they played around with people's lives, because, after all, they were all insignificant compared to them. How could the other demigods not see how awfully wrong everything was? And when Thalia came back to life, she didn't understand him either.
It led to years of war and countless deaths. The people who said Luke was being unfair and a whiny child; what a lack of information! If only they knew everything Luke had been through, he was sure they'd agree with him.
It took him the last, definitive battle in Manhattan to understand he had been the one misjudging everything. He had been revolted about something the gods couldn't help. It was partly their fault, but not all of it. So he sacrificed himself, in hopes that would fix things, fix everything he judged wrong.