"Call this an unfair generalization if you must, but old people are no good at everything."Bob knows that Alice is stupid: She's a woman, and women are stupid - never mind that Alice has a PhD and an IQ of 150, she's still a woman... and women are stupid, thus Alice is stupid. If Bob finally accepts that Alice is indeed smart, he might resort to claiming that she is not "really" a woman. Bonus points if Bob uses Alice not being stupid as an example of the principle that women are stupid - either because she's too smart to be a real woman, or as "the exception that verifies the rule". Also bonus points if "Alice" isn't even a woman, and Bob simply assumed a neutral Internet nickname to be female because he thinks the person is stupid. Alternatively, Alice actually does something stupid one single time - and Bob draws the conclusion that she is (and all other women are) always stupid. Of course, this is all simply Bob doing some really bad categorism: Racism if it's about race, sexism if it's about gender, ageism if it's about age, homophobia if it's about homosexuals, and so on. If Alice listens too much to him, she may come to suffer from Internalized Categorism. This trope can come into play in two ways: Either establishing or upholding. The first is often in the form of making a raging overgeneralization about a group - one that cannot possibly be true in all cases, and is often so outrageous that it might even be hard to find a valid example. The second is upholding the prejudice in the face of overwhelming evidence to the contrary, often with the help of Theory Tunnel Vision, Insane Troll Logic, and/or I Reject Your Reality. Sometimes combined with Straw Affiliation to make it extra insane: If you have Trait X you belong to group Y, and everyone in group Y are Z. For example, if you are a man who has long hair, you obviously turn over gravestones and nail live kittens to church doors. Because men with long hair are satanists, and satanists do that kind of stuff. Compare Nonsense Classification and Insane Troll Logic. When used by characters rather than the narrative itself, tropes such as Depraved Homosexual, Bondage Is Bad, and All Gays Are Pedophiles are often played as aggressive categorism. With the first two tropes, this come in the form of reducing people to their sexuality and reducing the sexuality to the sex. With the last two tropes, it comes in the form of deciding that everyone who have a certain quality X also has the unrelated quality Y*. This line of thinking easily leads to an Abomination Accusation Attack. When the aggressive categorism grows into being mentally unhealthy, it often takes the form of a phobia or a tendency to see everything in black and white. Often done by Racist Grandma, He-Man Woman Hater, Windmill Crusader, Straw Loser, or Noble Bigot, and often used to highlight how shallow the character's thinking is. This is often Played for Laughs at the character's expense or as a joke in its own right. Rarely done by more nuanced and Played for Drama characters, such as Troubled Sympathetic Bigot. May lead to Irrational Hatred. Note that "There Are Two Kinds of People in the World" is usually not this: Even when it's not a joke or metaphor, it's usually restricted to one parameter. Compare Double Standard.
—Moe Syzlack, The Simpsons, when Mr. Burns wants to join the bowling team