I’ve been a programmer working for various government agencies since the early 1990s and I can say with some confidence:
NOTHING HAPPENED BECAUSE WE WORKED VERY HARD FIXING SHIT THAT MOST DEFINITELY WOULD HAVE BROKEN ON 1-JAN-2000.
One example I personally worked on: vaccination databases.
My contract was with the CDC to coordinate immunization registries — you know, kids’ vaccine histories. What they got, when they got it, and (most importantly) which vaccines they were due to get next and when. These were state-wide registries, containing millions of records each.
Most of these systems were designed in the 1970s and 1980s, and stored the child’s DOB year as only two digits. This means that — had we not fixed it — just about every child in all the databases I worked on would have SUDDENLY AGED OUT OF THE PROGRAM 1-JAN-2000.
In other words: these kids would suddenly be “too old” to receive critical vaccines.
Okay, so that’s not a nuke plant exploding or airplanes dropping from the sky. In fact, nothing obvious would have occurred come Jan 1st.
Without the software advising doctors when to give vaccinations, an entire generation’s immunity to things like measles, mumps, smallpox (etc) would have been compromised. And nobody would even know there was a problem for months — possibly years — after.
You think the fun & games caused by a few anti-vaxers is bad?
Imagine whole populations going unvaccinated by accident… one case of measles and the death toll might be measured in millions.
This is one example I KNOW to be true, because I was there.
I also know that in the years leading up to 2000 there were ad-hoc discussion groups (particularly alt.risk) of amazed programmers and project managers that uncovered year-2000 traps… and fixed them.
Quietly, without fanfare.
In many cases because admitting there was a problem would have resulted in a lawsuit by angry customers. But mostly because it was our job to fix those design flaws before anyone was inconvenienced or hurt.
So, yeah… all that Y2K hysteria was for nothing, because programmers worked their asses off to make sure it was for nothing.