A theory should explain reality, not require reality to behave politely around it.

A useful explanation accommodates the world as it is, including the parts that do not cooperate. When an idea keeps requiring reality to have behaved differently, or dismisses every contrary case as an anomaly, it has stopped describing anything. The awkward facts are where the information is, and an explanation that cannot handle them is decoration.

When your model keeps meeting exceptions, resist the urge to explain each away individually. Collect them and look at them together. If they share a shape, that shape is pointing at a better explanation than the one you are defending.