Haskell - laziness can be exceedingly hard to reason about. Also it takes a lot of experience before you start designing your purity boundaries well. Ocaml - f

Haskell - laziness can be exceedingly hard to reason about. Also it takes a lot of experience before you start designing your purity boundaries well. Ocaml - figuring out the things surrounding the language (dependency management, concurrency, formatting, linting, etc)