Back in 2003 or so, my boss showed up at my desk at work, and looked like he was about to blow a gasket. There was a hack that was on the news, and it was getting featured in news stories all over the world.
He basically said he was going to fire me if it turned out it was my fault. (I built the servers that held the data that was compromised.)
Within a day, it turned out that it wasn't all the data, it was just one person, who had a lot of famous friends.
What had happened was that someone had accessed her account. The way that they did it was by guessing her password. Her password was the same as her dog's name, and she was a celebrity known to be seen at events with her dog.