Yeah but nothing I said disputed that. Practically all languages have concurrency built on top of an inherently single threaded execution environment. The two s

Yeah but nothing I said disputed that. Practically all languages have concurrency built on top of an inherently single threaded execution environment. The two standouts are Erlang based languages and Go. My point, coming from Python, was that whenever I can I write the entire application as an asyncio app, which cuts down on the function coloring problem. That doesn't mean you don't have to be careful, it's super easy to accidentally block the event loop.