Features that need more love

In this thread, we discuss programming language features that aren't as popular as they deserve to be.

Erlang's Binary Comprehensions
Whenever you hear people talking about Erlang, its always about the concurrency model, or, if Joe Armstrong is lucky, the error handling. I think it's a shame, because it makes handling raw binary data actually enjoyable. IIRC Haskell used to allow you to use comprehensions on any monad, not just lists, so they could have had it if the past had worked out differently.

How do you know a feature isn't loved enough? I think users of a language should try to fully understand their language when possible and thus learn of most features. Of course, features may work together in amazing ways you didn't really expect to create some intersting and maybe useful code.