Isn't Concurrency a Good Idea?

Nojers is built around having the event loop, which basically gets filled up when if you want to do IO work. It takes care of executing other things until there is a response to your IO work request. So this is basically how it achieves concurrence. But what all of these languages as mentioned in common is that it's not trivial,. Like really getting things concurrent and really doing things in parallel is not trivial there. And let's just say that there's a lot of brain juice you have to put into these kinds of programs to not make mistakes. When I was working on Akka with Java, we could always switch over to what is the name of that framework? It's