This is a very good question and everyone has their own answer for their own reasons. I thought I'd explain my philosophy to you. The way I use photoshop is as a digital darkroom. I use it to enhance what the camera captured and to help bring out more of the subject in each image.
Here's the image as it came out of the camera. I was happy with the composition but felt it could use just a little oomph.
So I warmed it up a bit to make the color really pop. And I sharpened just a little around the wings to help draw the eye to that part of the image.
And here it is after a little artistic editing. I've converted it to a warm black and white, darkened the background a bit and sharpened her eyes. I literally gasped out loud when I saw how this image turned out.
With some cloning, I was able to widen the white from the window and pull it out through the whole background so all that remains is this little cherub.
So thanks to the magic of Photoshop I am able to provide the families I work with the best possible images of their loved ones.