Anvilicious: Seuss's aesops are not delivered gently.
Interestingly, he usually didn’t write his books with morals in mind. He preferred to let it grow out from the story, saying “A kid can see a moral coming a mile away.”
Crazy Awesome: The circus and zoo featured in If I Ran The Circus and If I Ran The Zoo.
Downer Ending: The Lorax ends with the forest gone, the animals gone, and the Lorax gone. Only the Once-ler remains, who regrets his actions. However, there is one ray of hope: UNLESS. If the boy can regrow the forest and protect it, maybe the Lorax will come back.
Fair for Its Day: Seuss's attitude towards the Japanese would not go over well today, but it was nowhere near as extreme as many people's at the time.
Heartwarming Moments: The Lorax originally had the fish, chased out of their lake by pollution, say that "I hear things are just as bad up in Lake Erie". But "People indeed cared a whole awful lot,/ And worked very hard, and better it got." (to paraphrase the book's ending) - and so Dr. Seuss removed the line.
Misaimed Fandom: Horton Hears a Who has been co-opted as support by many pro-life groups, who use the famous line: "A person's a person, no matter how small" as their rallying cry. In truth, Seuss was commenting on how America was basically ignoring the rebuilding needs of post-WWII Japan, and that line in particular was intended to send the message that regardless of the fact that we had just fought a war against them, treating them that way was simply not right, and would probably engender further resentment against the United States.
The man himself wasn't pro-life and sued a pro-life organization for using the phrase on their stationary.