Scala is one of the very few languages that makes functional programming comfortable and is among the handful able to do higher kinded polymorphism and to encode type classes. You can probably count with one hand the number of languages in which you can express Haskell's powerful FP abstractions and Scala is one of them.
You cannot express libraries such as those in Typelevel (Cats, Shapeless, etc) or Scalaz in languages like Java, C# or F# for that matter. The only other comparable languages in expressivity, maturity and potential are OCaml and Haskell, with OCaml being very similar in spirit, but less popular (and F# is no OCaml ;)).
Of course, you will never feel this unless you actually start using the language, getting past the initial hello world and Javaisms. This problem was coined by Paul Graham as the "blub paradox": you can only notice inferior languages, abstractions and paradigms to what you currently know, but you can't easily notice superior ones, unless you make an effort to learn more. The great thing about Scala is that it allows a gradual migration and although this expressivity can be seen as a weakness, it's also why Scala is probably the most popular FP language.