There are good sides to GAD. I've tried over the years to steer my paranoia into being able to identify real threats, problems, weaknesses in systems where other people have glossed over any issues. Many common people just don't think about what could go wrong, even when they try. But for someone with GAD, it's possible to focus in on a complex process, say in a large business, and easily find issues that need to be addressed. I've always tempered this seeming negativity (many people in the professional world can see it like that) by surrounding myself with good natured people whom I trust. I'm upfront with them about my personality style, and then I use their optimism and sense of creativity to temper my own ability to find what's wrong. In this way, I use them to tell if the problems I've found are really as significant as I may want to believe.
Another upside is that I've found I can research topics to a degree that others are unwilling or unable to do, and I can typically easily recall the information. This is again helpful in a business setting when one is never certain when a topic may become relevant, however remote the subject.