Maybe it comes from being a Java developer but I believe that the ease of multithreaded programming is ridiculous. I mean, one paradigm lets you handle concurrency of multiple requests waiting for I/O <i>and</i> the parallelism of multiple CPU cores. If your language and runtime and frameworks for it were built to be threadsafe from day one and you have all the primitives to do it well (e.g. somebody didn’t sell you some crackpot scheme like Actors) it is astonishingly easy.