It is true that _most_ functions do not have side effect and that this is very liberating (makes it easier to refactor and maintain). Also, most of the time whe

It is true that _most_ functions do not have side effect and that this is very liberating (makes it easier to refactor and maintain). Also, most of the time when there is a side effect, it is clearly visible (due to using a stateful abstraction or library). So all in all while stating "every function has no side effect" is incorrect, I still share your overall feeling.