Another cool Photoshop trick

Doesn't this look real?  To the untrained and semi-trained eye, the foggy effect looks pretty authentic.  Not counting you, Photoshop Jedis, I know you can pick out everything that has been digitally altered.  Light Stalking has shown us again how to create a realistic effect in Photoshop.  Create a mist effect simply by adding a layer filled with white, then adding a mask with a gradient on it.  I tried it.  Check out the before and after: