re: "...I have to say it also cheers me up a lot, that my make-over is seemingly so great, that nearly everyone mistakes it as the original..."
That is exactly the way you should take it! There are a million different ways to modify a high quality, perfectly lit, perfectly color balanced, perfectly exposed realistic photo to look eye-catching, and have exaggerated, or even completely bizarre colors and tones. There are a huge number of native PS tools, plugins and actions that anyone can use to do this that require nothing more than the press of a single button.
However, it is VASTLY more difficult to come up with a set of steps to reverse such a process, especially if you don't have a copy of the starting image to refer to. In fact, in many cases, a reverse process simply can not exist unless a very talented artist essentially reconstructs missing data by completely manual methods -- almost like colorizing an old black and white photo.
As a simple example, suppose someone takes a picture of colored lights and then processes it so that it becomes a sepia toned print, ie, the hue of all the lights is now the same -- one hue in the red-orange part of the spectrum. The processing has reduced a wide range of hues to one. No algorithm can spread out the hues again. An artist can guess what colors they might have been and paint those colors in, but they'll never know for sure if they got it right.
From what you have said, it sound like you are very, very good at recognizing realistic colors and tones, and you simply do whatever it takes to bring the highly processed version of the image back to a natural look.
So, as an example, attached is an image that came out of my camera a couple of years ago as a normal, reasonably well lit, exposed and color balanced photo of a woman. To make it look somewhat like the image you posted, I processed my image using Portrait Professional (with many of the adjustments set unusually high) followed by an overall cross processing effect. I would love to see how close you can come to the original (which I'll post later) and learn how you do it. I know that I would have an extremely difficult time returning this image to a normal appearance.
Cheers,
Tom M