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). After a couple of hours of work, and having already soldered in about half of the 40 or so 14 and 16 pin I.C.s, I realized that I'd put them all in backwards! Needless to say I spent the next few days de-soldering—a much more tedious process.
The applicability of my rule to yesterday is that I chose yesterday to rebuild Windows XP on my main laptop. I'd already started to commit to the process by backing up various bits of the system that I don't normally backup as a whole, so I thought I might as well just do it.
While it wasn't a complete disaster, I did forget to backup my bin directory where I keep assorted utilities that I and other people have written. I also lost my Downloads directory, which while not critical, was the accumulation of a number of years of downloaded papers, semiconductor data-sheets, specs and so-on. Now, along with all the other stuff I have to re-install, I have to try and figure out what I really need back.
On the bright side, my machine is faster again (I think 18 months of compiling and linking badly fragments your disk).