| Quote #4
"But they're stories," I said. "They're—myths, to explain lightning and the seasons and stuff. They're what people believed before there was science." (5.120)
Percy believes the Greek gods are a lie. A myth is kind of like a lie – it's not something that's true, but rather something that's interpreted or used to explain things that are true.
| Quote #5
"I should've told you the truth from the beginning." His voice trembled. "I thought if you knew what a failure I was, you wouldn't want me along." (16.62)
There are several instances in which people lie out of insecurity, worry, or in order to protect themselves. Here, Grover (who normally never lies) says a false thing in order to ensure his future. He worried that if Percy knew that he had failed on a quest before, Percy might not take him along on his own quest. If Grover didn't get to go on this quest, he might never get his Searcher's license. If Grover isn't able to get his Searcher's license, he will never be able to pursue his life's dream and go in search of Pan. He lies to protect his dream.
| Quote #6
I'd stay here, happy forever, playing games forever, and soon I'd forget my mom, and my quest, and maybe even my own name. (16.248)
The Lotus Casino is one big deception – it's a trap. It is the coolest and comfiest place a kid could ever dream of with endless amounts of money and games and good and luxury. But the Casino erases memories, making people forget how long they have been there and why they are there. Do you think any god intentionally created the Lotus Casino just for the purpose of trapping Percy and his friends? Or do you think the Lotus Casino is simply just a random obstacle in their quest?