I dont think people should do it, it creates a false image for others. Like I don't hate it, but sometime they take it to extremes and people think that how they have to look like and usually only bad things come out of that. If it's something simple like clearing up the skin or changing the hues a bit, I understand that, but they change your whole face and body so that you don't even look like the same person.
My favorite element of art is color, I love seeing tons of color and the different ways people color. My favorite principle of art is emphasis, it can show a lot of emotion and can give off a unique vibe depending on how they use it.