There is a brief moment on the green which occurs several times a round for 99.99% of golfers, but is only used effectively by a small minority.
It's the moment where you miss a putt and the ball's behaviour surprised you in some way. If this happens, it means that you mis-read the putt. Your simulation of line and pace was incorrect, perhaps only slightly, but enough to miss.
I've observed that often golfers still blame the execution of the stroke, in spite of this.
This is an example of "anti-learning" where the wrong distinction is made, possibly resulting in attempting to fix the wrong thing.
What did I miss?
Take a moment to make the distinction that it was the plan not execution, that was the prime cause of the miss. Before you leave the green, take a quick look to see what you missed.
Say you had an uphill 10 foot putt which you anticipated was slightly right to left, but in fact rolled dead straight and missed right.
Let's use the clock analogy where 12 o’clock is straight downhill (and 6 o’clock vica versa). Your read was that the ball was positioned at, say, 5 o’clock (uphill and right-to-left) but the roll proved you were actually at 6.
Green reading is pattern recognition, drawing on past experiences to make sense of the topography in front of you. When you are fooled, use the opportunity to "re-see" the green knowing what the ball did. Scaled up over time, this habit makes improved reading inevitable.