There were a few ways things could have gone wrong at midnight on January 1, 2000, depending on who you asked.

WTF Is Y2K?

Some people feared the worst: that a computer bug known as Y2K would launch nuclear missiles and cause planes to fall from the sky. Other people insisted that this thing called Y2K was a hoax, not worthy of a second thought. And at the stroke of midnight on January 1, 2000, here’s what happened: not much.