+1. People get themselves worked up about words like "monads" and "algebraic data types," but using those things is not difficult, and the amount of guarantees

+1. People get themselves worked up about words like "monads" and "algebraic data types," but using those things is not difficult, and the amount of guarantees they give you about your code is so far beyond anything else out there that IMO it's not worth doing functional programming unless you have a proper type system together with monads.