White Balance is something that defines a picture. The human eye is very versatile when it comes to adjusting to the lighting conditions. You can actually try this out to get what I am saying. Take a red cloth and cover a window (during the day) with it. Now make sure that one eye has the red glowing (from the light from the window) cloth in it's background and the other doesn't. Now see a white sheet of paper (or even a visiting card) placed right in front of your face, about a foot away. Now look at it from one eye, and then with the other. If done correctly, you should see the same piece of paper in two different colors. The camera on the other hand cannot adjust that well. I have realized that pictures clicked under white light have a tendency to be cooler than you want them to be. I am really lazy when it comes to post processing, and prefer to leave most of my snaps untouched, unless it's a shot (not a snap) and prefer to tinker with the white balance on the camera itself. For eg, when clicking under white light, I make the picture a bit warmer by setting the WB to 'Flash'. This one though is warmer by virtue of post processing.