A lot of people don't believe in curses. A lot of people don't believe in yellow-spotted lizards either, but if one bites you, it doesn't make a difference whether you believe in it or not.
This is a statement from the narrator which implies that regardless of whether Stanley's family or the reader believes in curses, the bad luck that they are the recipients of is undeniable. And, just as the lizard's bite is deadly, so is the supposed curse that Stanley's family is under.
His muscles and hands weren't the only parts of his body that had toughened over the past several weeks. His heart had hardened as well.
This statement describes Stanley's development at Camp Green Lake. Although Stanley is used to being picked on, he exhibits no sympathy for Zero when Zero reveals that he cannot read. Instead of trying to help Zero, Stanley instead decides to reserve his energy for himself. This is not purely Stanley's fault, the tough people that he is surrounded by have influenced him and now he is becoming like them.
"If only, if only," the woodpecker sighs, "The bark on the tree was just a little bit softer." While the wolf waits below, hungry and lonely, He cries to the moo-oo-oon, "If only, if only."
This is not so much an important quote as it is a recurring quote in the book. Although slightly changed by each person, these are the basic lyrics to the song that Madame Zeroni taught Elya Yelnats and that was subsequently passed down through generations until it reached Stanley and Zero. The lyrics of the song show that even wolves and birds wish that life was easier. It is a fitting song to be sung by the Yelnats and Zeroni families, two families that have had bad luck and hard lives.
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