If you just stick to the idea of type classes, then yeah, it is simple and abstract, even for constructor classes like Functor and Monad. But the reality of typ

If you just stick to the idea of type classes, then yeah, it is simple and abstract, even for constructor classes like Functor and Monad. But the reality of type classes in Haskell is not as simple, I think. Defaulting rules, "deriving", Paterson conditions, instance coherence, functional dependencies, etc.