1. The two great insights of Dr. Seuss's Green Eggs and Ham were that monologues are more interesting if your characters move rapidly across a wide and dangerous array of terrain, and that you can tell a compelling story using only 50 different words. Bill Watterson was powefully influenced by the first of those insights, and not at all by the second.
2. Mo, the bully who torments Calvin, later went on to be Donald Trump's Nickname Strategist Timmy Jenkins, as interviewed by Steven Colbert. In kindergarten, of course, he was not normally that articulate, but he already had promise ("Hey twinky, give me a quarter... for the Let Calvin Live Through Recess Fund"). And the self-awareness to answer Calvin's philosophical challenges to his bully role with "Because it's fun".