Stage 1: The first thing that newbies learn about is that there is an Exposure Triangle. Some Peterson guy is said to have wrote about it in a book. I haven’t read it. I’ve seen his videos. Maybe his intentions are good and he knows what he’s doing. But a heap of newbies don’t “get it”
Stage 2: Eventually it dawns on people that the Exposure Triangle has a Fourth Side.
Stage 3: After rummaging around, comparing effective techniques of whether to use P A S M or figuring out which metering pattern is better – Evaluative Matrix vs Centre Weighted vs Spot vs the classical Sunny 16 rule vs Interpreting the Histogram vs ETTR and asking themselves where the hell they put the white towel / Kodak 18% Neutral Gray Card or the XRite thingamajig, someone mentions that Adams chap who wrote about the Zone System. And bang! Smack on the head. There is no Correct Exposure. There is what the camera measures as an instrument and what the artist (you) choose to convey and interpret. The two are not and do not have to be the same thing
Stage 4: So far, so good. People are shooting decent shots. But they’re not spectacular. Like those gorgeous smooth skin tones and sharp, clear irises of the girls in the portraits. And so on. So we ask, how on earth does so and so get this shot with his iPhone but we can’t and we’ve almost spent as much as a Nikon D3s? And the penny drops. We can’t. If we REACT to the scene. Often times, the pros don’t react, they’re pro-active. They light up the scene the way they want. Or gain a vantage point if they can’t control the light. And having done their utmost to light the scene well, they touch up with Photoshop. Delicately and Emphatically. Not the other way around.