[s4vi0r]

Fwiw, the monad quote is actually pretty digestible if you know what monoids and functors are.

A functor is a container that you can reach into to perform some action on the thing inside (e.g. mapping the sqrt function on a list of ints). The endo bit just tells you that the functor isn't leaving the category (e.g. an object, in this case a Haskell type, when lifted into this functor context is still in the Haskell 'category'). A monoid is something we can smash together that also has an identity (e.g. strings form a monoid under concatenation and the empty string as an identity). So, in other words, monads are functors ('endofunctors') that we can smash together using bind/flatMap, and we have an identity in the form of the Id/Identity functor (a wrapper, essentially - `Id<A> = A`).