One of the most important things I try and teach students is the difference between white point and white balance. Most believe if you grab your eye dropper and hit the area you believe should be white and click the mouse you will have established your white balance. What you have really done is establish a white point. While the colors might appear to be more "on target and corrected" you actually just through quite a bit of information away. By clicking on what you believe to be white, you have actually created a "white point" A white point is where there is no information at all in the white. If you look at the info palette it will read 255R, 255G, 255B - This is also the same as "paper white" if printed not ink will be seen in this area.
White balance is a color neutral point where there is still detail in the white area. Yes you can hold detail in the snow, or the white dress, or the white shirt, but often it is a very delicate area to retain the information in. Therefore it is important to use the proper tools to find your white balance. In Photoshop I find the white balance eyedropper is the best place to start, in LightRoom the white balance tool is the best. Best of all you are bringing the colors that might be biased for a number of reasons into neutral territory. This is a great place to start your photo editing. As a further tip- white a neutral white balance is a great place to start, you still may want you make your image a bit warmer or cooler depending on your personal preferences.
I hope this little tip helps. I am amazed at how many of my students find this confusing. I will admit though, it took me a while before I completely understood the situation as well.