Many developers first learn asynchronous JavaScript through syntax before they really understand flow. That often leads to code that works but still feels unpredictable when callbacks, promises, timers, and network requests start mixing together.
The biggest unlock is thinking in terms of scheduling. JavaScript runs on a single main thread for your code, but the environment around it can manage timers, I/O, and browser events. When that work completes, callbacks and promise continuations are placed into queues and executed when the current stack clears.
Promises improved readability because they let asynchronous work behave more like values in motion. `async` and `await` improved it further by making sequencing easier to read. But readability does not remove complexity. You still need to understand what is parallel, what is sequential, and where errors can escape if they are not handled deliberately.
In practice, good async code is less about syntax and more about structure. Group related tasks, avoid accidental serialization, fail clearly, and make loading and retry states part of the design rather than afterthoughts.