> The frustration with interruptions is that they introduce a sudden increase in required working memory

I've wondered the same - though never been able to put it into such concise words. I formerly worked as a Mechanical/Controls engineer and did not feel the same frustration with interruptions at the time despite being an equally challenging industry (as far as my experience went). My conclusion is that the hard constraints of a physical system keep the problem space (and thus the required working memory) relatively small in the physical world. When you're writing software that has no physical manifestation, the problem space is typically massive since the constraints are fewer.