"What's wrong with Monads is that if you go into a Monad you have to change your whole syntax from scratch. Every single line of your program changes if you get it in or out of a Monad. They're not polymorphic so it's really the old days of Pascal. A monomorphic type system that says 'well that's all I do' ... there's no way to abstract over things. " [0, 53:45]