In times of crisis, every American supports his President. This statement is an overgeneralization because it assumes too much to be proven possible. Until every American can be contacted and surveyed, this statement cannot be proven valid. We can correct this mistake by clarifying how many people profess to support the President, and under what conditions they would not. Beware of statements that are too broad to be valid or contain all or nothing language.
All birds can fly.
Many young children make this overgeneralization when learning how to categorize the details of their world. They have learned a general concept, but do not yet understand its exceptions. Sometimes, generalizations are used to make a clever point, so their application is metaphoric suggesting a message rather than blankly overstating something. Cottleston, Cottleston, Cottleston Pie, A fly can t bird, but a bird can fly. This overgeneralization is knowingly created to punctuate a clever bit of wisdom with a humorous twist.