Intuition, instinct, underbelly, gut, call it what you will.
Up until a few years ago my cameras were bolted to a tripod, shot selection and shooting was a far more considered and time consuming process, much the same as when there was a paint brush in my hand.
Now, with camera in hand, and the very nature of what it is I'm doing and where I'm doing it, the selection and shooting process by necessity has to be largely governed by intuition, instinct, underbelly and gut.
I'm not at all sure this is facilitated by looking at a lot of pictures, but believe it is something that is there, or indeed not.