"The problem is that most common code inherently involves state -- business apps, games, UI, etc. There's no problem with some parts of an app being purely functional; in fact most apps could benefit in at least one area. But forcing the paradigm all over the place feels counter-intuitive."
Fallacy Of Is To Ought
Why or how ought it "feel intuitive" to someone who's been taught and is used to think by a different paradigm?