Behind the scenes, no call happens instantly -- it only appears instant if the call is blocking at the source code level. There is no guarantee that in the fut

Behind the scenes, no call happens instantly -- it only appears instant if the call is blocking at the source code level. There is no guarantee that in the future the compiler/CPU will prevent other actions during a 'blocking' call. Blocking syntax is simply for the convenience of program structure. Whether the call is blocking/synchronous or non-blocking/asynchronous is just a decision that was made at the language design level. Hence why node has both sync and async for file I/O. Await/yield allows us to keep the concerns of the function in one code block rather than splitting them up -- regardless of whether the source author wrote the method as 'synchronous'. Thinking about a program as async from the start avoids a ton of problems down the line.