[anon_dev_123456]

Elixir - Pattern matching for function signatures. So many conditional statements just nuked from orbit.

[jetti]

That's a good one. Once I started making use of that my functions are a lot smaller and cleaner.

To add to Elixir, I would say the ease of interoping with Erlang. It allows me to easily take advantage of the massive Erlang libraries that are built in (such as crypto) without having to do anything extra.