>>sberen+(OP)
Well-written and valuable for insight whether you have similar personal experience or not.
As someone who does hardware and software as well, I relate to the challenges of making something you can hold; it's very easy to underestimate the challenge difference between the two.
Your Murphy's law references are spot on; I feel comforted reading I'm not the only one this happens to! Misery does love company, and it's important to hang on that I think, so that you don't lose hope :)