Has your child ever come back from school crying because their friend has the best backpack ever and they're absolutely without a doubt 100% certain they can't be happy unless they have one just like it? Yeah, that's what we call jealousy, with a little competitiveness mixed in for good measure. And hey, it's a very human thing to feel, especially when there are so many awesome backpacks out there.
Each protagonist in Yertle the Turtle and Other Stories has a major jealousy thing going on, constantly salivating over what someone else has (even if, in Yertle's case, "someone else" changes depending on what he sees right here and right now). When nothing you have is good enough for you, what everyone else does have is oh so much better. That's just the way of the jealous heart.
Q: Why does Yertle hate the moon so much? It's just the moon!
A: Because the moon has what Yertle wants: to be higher than everyone and everything. (Little does he know there are things higher than the moon…)
Q: Why is Gertrude so upset about Lolla-Lee-Lou?
A: Kid, Gertrude ain't so happy with herself, and she wants what Lolla-Lee-Lou's got. Or so she thinks.
Q: Why do the rabbit and the bear have to brag so much?
A: Because they're jealous and want to prove themselves to be the best. It's not very becoming, is it?