Y2k was a big fear that i thought people didn't think all the way through. What's going to happen when you're computer hits the big 00 year? Well, another year and day of normal operation happens. Will your computer take a **** when you try to modify a file made in 99 during the year 00? No, the file you modified just gets a new last accessed and last modified stamp of 00 instead of 99. The one thing i'd find funny is if xp had come out earlier and supported 2 digit years. That way when the clock would strike 00 then xp would say "you're a pirate, the date is wrong!, plz check out WGA!"
The only thing that really got ****ed up a little bit in the minor sense when the clocks struck 2000 was the atomic clock. Perhaps there was some more **** ups with technology, but ultimately, computers don't have sentience to be able to get confused like people were treating them would when the date goes from 99 to 00. The only time i see programs getting confused because of a date change is if that program was designed to do so, like xp (it screams bloody murder if you change the date to something in the past because of that WGA crap since ms doesn't trust their customers and treats them like they will do wrong on their part).
Probably some more stuff in y2k got ****ed, but ultimately, i didn't get very excited about it. I had a 1980's mac that had two digit year dating. I changed it to 00 manually one day, nothing happened except the computer thinking that it was the year 00.