“Anxiety is incredibly pervasive. People have a very strong intuition that trying to calm down is the best way to cope with their anxiety, but that can be very difficult and ineffective,” said study author Alison Wood Brooks, Ph.D., of Harvard Business School.

“When people feel anxious and try to calm down, they are thinking about all the things that could go badly. When they are excited, they are thinking about how things could go well.”

So excitement makes people optimistic? I always thought it was vice versa. 

It's an interesting question.  Perhaps it's dialectical.  What I took from the article is that when you're feeling anxious, try to take your focus off of what could go wrong (especially if it's not that likely), and instead try to imagine things going well, and allow yourself to feel excited about the prospect.  I'm sure there is plenty of room for questions for more research.

That's a good tip! Will practice...