miniblog.

Cases where it makes more sense to use concrete types rather than generics, even if you can be generic:

I'm not convinced that offering the staging area is a good default for git. It's an abstraction that newcomers have to learn before their first commit. Subversion style "commit every tracked file" isn't as pretty (`git add` is general) but it's the common case.

I really like the one-module-per-file model of JavaScript or Python. If you're storing code in files, you might as well leverage file boundaries. If modules are a separate abstraction (e.g Rust, OCaml), it's harder to learn and choose how to organise code.