In my experience, "small fraction of all cases" is inaccurate - in my C it's probably 1/3 to 2/3 of cases, depending on how much I structure my program to allow for it. For instance, synchronous processing of messages makes it relevant in many more cases, but has obvious costs (which isn't to say they aren't sometimes worth bearing). It is still true that there is a significant fraction of coding where it does not apply, and which must be treated specially.