Affect therefore regulates how we solve problems and perform tasks. Negative affect can make it harder to do even easy tasks: positive affect can make it easier to do difficult tasks. [...]
Imagine a plank 10 meters long and 1 meter wide. Place it on the ground. Can you walk on it? Of course - no problem. You can jump up and down, dance, and even walk along with your eyes shut. Now lift the plank 3 meters in the air. Can you walk on it? Yes, although more carefully.
What if the plank were 200 meters in the air? Most of us wouldn't dare go near it, even though the act of walking along it and maintaining balance should be no more difficult than when on the ground. Why would a simple task suddenly become so difficult - impossible, even? Tell yourself all you want that if you can walk on the plank on the ground, you can still walk on it in the air. You still won't walk along it, let alone jump and dance or, heaven forbid, close your eyes while walking. Fear dominates.
Why should affect have such an influence?
Go read the article. You'll be glad you did.