Love the shadows in the snap I took of fellow blogger Sam Javanrouh of topleftpixel:
We could have cropped this differently:
And we could shoot more. My favourite (and you need to click through several times to see it at large size):
My point: when you see great light and shadows, use them and shoot.
(Manual, 800 ISO, 1/50th second, f/2,8 with the 24-70mm lens in the 1D Mk4)