I use Java, Groovy and Scala on a daily basis and the only thing I dislike about Scala is the fact that they seem to have chosen to be as unfamiliar as possible

I use Java, Groovy and Scala on a daily basis and the only thing I dislike about Scala is the fact that they seem to have chosen to be as unfamiliar as possible to the average Java programmer. It often feels like "although we could have designed it in a way so that it is familiar to you, we chose something different although it means the same thing". Whereas Groovy tries to decorate existing Java classes and add some nice functional abstractions on top of them, Scala very often tries to enforce its own way of thinking or renaming identical concepts in a different way. Groovy is much easier to adopt in my mind because of that. You can gradually adopt Groovy and groovify your code as you progress your skills with the language. In contrast to that, learning Scala is harder, because it often requires a complete mental shift.