Since I spent a few years in the automation world, I found out more about the vulnerabilities that can be exploited that were more potentially catastrophic than even data loss. In a Wall Street Journal article, details are given about how portions of the US power grid were exposed in a unique way that hackers discovered.
If you are a football fan at all, think of the time spent every week by football coaches going over video of their opponent, looking for vulnerabilities that they can exploit in order to win a game. And each week there are changes made to adjust to vulnerabilities exposed. Our power grid and your data are more important than winning a football game, and there are people out there working hard to exploit your systems.
The best way to stay secure is to stay on top of the systems in place, and educate your employees on what they should and should not do. It is a never ending battle.