After losing the family's life savings in the stock market, Homer gets a job as a test subject for scientific experiments, one of which reveals the true reason behind his stupidity: a crayon that got stuck in his brain when he was a child. When Homer gets the crayon surgically removed, he becomes a more intelligent man — and soon learns that being smart doesn't equal being happy.
This episode contains examples of:
- Affectionate Parody: Of Flowers for Algernon.
- Back Alley Doctor: Moe, though he operates in his bar rather than a back alley. He even has cards of his shady business.
- Biting-the-Hand Humor: When Homer checks his stock numbers for Animotion, the stock name for FOX Broadcasting is "Huh, What Is This Crap?", which is down eight points.
- Crapsack World: Homer seems like a super-genius with the crayon removed from his brain. However, he later states his new IQ is 105, which is only slightly above average. The people of Springfield are just that stupid (including the ones said to be smart, like Lisa, Martin Prince [whose I.Q. is 216], and the members of MENSA on "They Saved Lisa's Brain"note ).
- Intelligence Equals Isolation: According to Lisa, as intelligence goes up, happiness often goes down. She even made a graph of it.
- Take That and Arson, Murder, and Jaywalking: When Smart Homer walks the streets looking for a place for smart people, he passes by places catering to idiots and morons, like Lunkheadz, The Dum-Dum Club, and The Disney Store.