Green Eggs and Ham, by Dr. Seuss
What we see in GE&H is a central conflict between two main characters. The protagonist, deliberately left unnamed, opens the action by railing against a mysterious, sign-holding dwarf. He does not like that Sam-I-Am.
Far from being upset by the protagonist's criticisms, Sam displays an unflappable calm as he offers what is traditionally seen as a universal sign of hospitality: food. In continually offering to break bread with the Protagonist, Sam could be interpreted as a martyr - the perfect host, the best friend, although continually rejected.
And yet, a twist is thrown into this mix. The food being offered - ham and eggs, is clearly rancid (a fact often overlooked by kindergarten classes), and suddenly, Sam's integrity is thrown into question. What kind of person offers spoiled food to his supposed friend? The Protagonist, at first seen as perhaps unreasonable in his dislike, is now more sympathetic; of course he does not like Sam-I-Am - either the man is too inexperienced a cook to realize that his food has gone bad, or he is trying to poison the man he claims to like.
And thus begins the central struggle between the two characters that lasts the duration of the book - Sam continually tries to talk the Protagonist into trying his food, and the Protagonist continually states what is clearly his personal philosophy, which is that he does not like green eggs and ham. The story employs the uses of various imagery to take this simple conflict to extreme absurdities. ("I will not eat them in a box, I will not eat them with a fox" - thus demonstrating the claustrophobia of domesticity, and immediately afterwards throwing a jab at the wiley Sam, whom the fox is clearly meant to represent)
While Sam continually tries to present the eggs and ham in different situations that may make them more appealing, the Protagonist simply repeats his rallying cry: "I do not like green eggs and ham, I will not eat them, Sam-I-Am!" An interesting insight can be found about the Protagonist by examining these words - it is significant that he does not define his tastes by listing this that he does like; he can only list things that he doesn't like. This process of self-analysis-by-elimination causes us to realize that the Protagonist, while seemingly mature, is actually quite insecure. He doesn't really know what he likes, he only knows what he doesn't like. He is an individual who presents a confident and even aggressive face to the world, while secretly being terrified that the world will see through his facade.
However, at the end of the book, a Protagonist undergoes an extraordinary development in character - he pauses for a moment of self-examination, and realizes that his identity cannot solely be based on rejecting the prospect of new experiences.
In this moment of self-discovery, the Protagonist does something revolutionary - he accepts Sam's offer of breakfast. And, in doing so, he find that he enjoys it, despite the green tinge. And a new phase of development is ushered into the Protagonist's journey toward maturity.
But what of Sam? What was his motivation to continually offer food to the Protagonist, despite the continued rebuffals? Is he crazy? A child? A villain? Or, perhaps, a fool?
I posit that Sam-I-Am is the Seussian adaptation of the classic Shakespearean Fool - the figure who is seen by all other characters as an idiot who knows nothing, but who possesses secret wisdom that he subtly shares with his "superiors" through riddles and jokes. The Fool is never taken seriously, even when it is obvious that he is the most knowledgeable character. However, the Fool knows everybody's secrets, and knows what must be done to resolve the conflict and bring about the happy ending.
And so, seemingly, does Green Eggs and Ham end - happily. But let us not forget that GE&H ends on a note of ambiguity - the Protagonist has eaten the eggs and found that he likes them, and by extension, Sam. Here, however, is where the story ends, and the consequences of eating the food is unknown. Does the Protagonist briefly enjoy a renaissance of self-discovery, before suddenly becoming violently ill with salmonella? If this is the case, what is the message Sam is trying to send? Perhaps that personal growth is inescapable and necessary, but can come at a price...