I've been doing so much time in single-threaded languages I wasn't thinking that Scala supported actual concurrency. (Which is silly, given its Java heritage.)

Different worlds -- I've mainly been focused on multi-threaded environments for the past 20 years. (Which is why I went so deeply into Akka: it's an approach to shared mutable state that doesn't require insane brilliance at all times.)

But it's wonderfully relaxing not to have to worry about all that crap when working in the browser...