The Mouse, The Fox, and The Goat
Seussville is filled with all sorts of creatures, and in Green Eggs and Ham, we meet the mouse, the fox, and the goat.
These characters are obviously part of Sam's crew, ready and willing to do whatever he says at any moment. Did you see how quickly that goat popped up from its compartment in the car when Sam asks, "Could you, would you,/ with a goat?" (106, 107). These creatures seem quite happy with their roles, and wear looks of utter contentment, if not sheer bliss, throughout the tale.
The Train Conductor and Ship Captain
If you ask us, somebody should have done some kind of pre-employment screen on these two. The train conductor conducts the train right off the tracks and onto the ship, all with a goofy look on his face. We find that same look on the ship captain's face even when his vessel is sinking. What's with these guys? Maybe they've been eating too much green eggs and ham.
Like the mouse, fox, goat, conductor, and captain, the passengers on the train wear looks of blissful contentment, no matter what perilous situation they find themselves in. Adventure, it seems, has a relaxing effect on most of our characters.
No matter the reason, all this happiness sure adds to the happy-go-lucky "Tone" of the story.