Having the last line of a function always be returned was one of the stepping stones to functional programming for me as it was now finally concise to write pure functions compared to pre-ES2015. Still post ES2015, if the arrow function body isn't a one-liner, you have to put back your curly braces and return keyword.

After a brief time in LiveScript, I've since mostly written in the ML families (Elm & PureScript) where this is the default behavior.

And I still like/use CSON over YAML in some cases.