Photographers have so many choices on how their photographs will look it allows for individuality to stand out. Most photographers find a look (or photoshop preset) and stick to it. Now they can have plenty or reasons but the need to "finish and move on" will never be one they admit to (but is probably the correct answer... and yes I understand that time is money).
For me I just can't and when I tell clients that "our work is just beginning just when other photographers are finishing", I ain't kidding. I want to make sure each photo is presented in it's best light (literally)... but what is that? I work on a photo and then work on it some more and then try something else.... etc
Here is an example of four different looks of the exact same photo. The top is the out of camera and the rest were me messing with exposure and detail. Below is a B&W rustish color with the blown out sky. So many choices... this is what keeps me up late into the night. (Yes even this montage would look cool in a book)