A polarizing filter has been permanently attached to my lens for so long that I simply take it for granted. I rarely remove it but yet continue to be surprised during those condititions that demonstrate just how magical and dramatic the effect can be. Using a polarizing filter can have more impact and value than the lens itself.
The following two images were created minutes apart with different polarizing intensities. The contrast and saturation in the wet sand is significant.
Below is one more example from a slightly hazy day of flying. From 1000 feet above, a polarizer can cut back those reflections, giving us a great view of the ocean floor.