I was reminded, yesterday, of an old rule of mine; “don't do important things when you're feeling sick or tired”. My rule dates back to some time in my mid-teens when I spent an evening soldering up a kit for what was then known as a VDU (in this case a single board that acted as the display part of a dumb terminal). Unfortunately I was already tired and excited (I'd been waiting for this thing for a couple of months).