I suppose the key to this is in the last line - you're implying something that doesn't wait is better. That'd be actors; your creation, yes? :)

But out of interest, the syncing that you apparently dislike but which actors sidestep by having a receiving queue, said syncing allows for messages to be processed when the receiver is ready (obviously). That's a time overhead. If actors have unbounded queues then there's a memory overhead (and one which may grow infinitely on a finite machine if someone isn't processing their messages fast enough).

How do actors handle that? If I'm talking rubbish some reading matter is welcome.