For a minute there I thought you were still using IE4 and was about to ask if you were crazy

Some people would agree I am, but for other reasons

BSODs are generally caused by bad drivers or bad hardware but Windows takes the blame for it.
Ditto.
If it is a standalone machine that nothing else connects to then sure, leave it unpatched but if other machines do connect to it even if it isn't on the internet then you should patch it.
It was little irresponsible, but not so much. It was a file server shared by four people for non critical content. I'had meant to put it down for years and never did, to the point that its uptime became object of fun; eventually we relocated and transportation would last longer than any UPS available around would. So, I had to power ir down.