> To be honest I feel like the functor concept is too abstract and subtle to the point where it's probably not very useful in the context of programming. I thi

> To be honest I feel like the functor concept is too abstract and subtle to the point where it's probably not very useful in the context of programming. I think it's a small convenience to have the programming language automatically derive `map` instances for you, but I think you're right for pretty much the same reason group theory's huge but monoid theory barely exists: the `Functor` typeclass is too simple to do anything interesting with it.