I talked about images from this place before. This is from a little stream in Zion National Park. It is an extreme example of how important it is to know the right white balance. Below I show a single shot from this place using the as-shot white balance, auto Lightroom white balance, daylight, cloudy and shade, and lastly the white balance taken from the neutral patch on a x-rite colorchecker passport. These images, apart from the camera landscape profile are using completely default processing values.
I made this hextich using the print panel in Lightroom and added the text in Photoshop. Click for bigger. As you can see, both the camera and the auto white balance get this completely wrong. The as-shot and auto are far from reality. The rocks on the top left should be orange as they are standard Zion sandstone. The water should not be Cobalt blue. I should also point out here that this image was made at the bottom of a steep canyon where one cayon wall was lit by the sun, causing a very strong glow light in the area where we were. The water is reflecting the light from this canyonwall. Assuming different white balances gets very different results. You can see the results from assuming daylight to shade. Each is giving very different, but much more pleasant results than "as shot" or "auto". The last panel shows what happens when using the neutral patch on my white balance card on the x-rite passport. It is even warmer than "shade"! Of these, I think I prefer shade as the colors are more interesting. One example in which using a white balance card actually is not that helpful. I came accross many more situations like this in the Narrows and other places where the light was just very strange and where my eyes were not seeing what the white balance standard thinks I should be seeing.
EDIT: I posted another illustrative example in a recent blog post.
See more images from Zion in the link.