"With node.js... you really, truly and most awesomely don't worry about race conditions."

Most of node.js's fanbase well and truly believes this nonsense, that you can't have race conditions simply because there is no pre-emption of your running code. In fact, single-threaded, event-based logic can very easily end up in situations where the timing or ordering of network frames impact a response in an unanticipated manner.