Each programming language has its own specific standards. Scala is not an exception and also comes with its own coding style specificity.
When a programming language provides operator overloading, the learning curve increases most of the time because of the syntactic sugar it brings. After all more of operations will be expressed as not meaningful (at least in first approach) symbols. Scala also comes with its own syntactic sugar that can be applied in a lot of places: sequences, functions or conversion.
Scala has a lot of syntactic sugar. Despite the fact that most of times it pretty simply understandable, it occurs often that it increases the learning curve. One of symbols widely used in Scala and hard to understand at first contact is the underscore.