Something occurred to me the other day while I was solving my Rubik's Cube. I solve it upside down. I solve from the bottom up. White side first, yellow side last.
I learned this trick to avoid reorienting the cube. Who wants to keep changing your point of view just to keep track of your progress?
Rules constrain the behavior of the cube so I know certain things will happen to edge and corner "cubies" even if I don't see them directly. (By the way, a "cubie" is a nickname for the individual pieces on the cube.) In my case, if a cubie has a white sticker on it, then I know it belongs on the bottom (hidden) layer. If it has a yellow sticker, then it's going somewhere on the top (visible) layer. I don't have to constantly peek at the bottom of the cube, I can use other visible cues to ensure it gets where it belongs.
Then it hit me! This is Point of View, or POV in literary circles. This is the perspective the story is told to the reader. How is the narration revealed? First person, third person, etc.
When you write a story, it is important to maintain a consistent POV. By consistent, you don't switch perspectives mid-chapter, mid-scene, or mid-paragraph without giving the reader an obvious cue. (Of course you can have multiple POVs in the story, and it's a challenge to pull off successfully. Maybe I'll cover that another time.) The most common convention is for a story to be told from a single POV, or perspective.
Too many POV shifts can be jarring to the reader. Imagine how frustrated you would be if someone constantly reoriented the top color on your Rubik's Cube after every turn you make to solve it.
It's easy to catch POV mistakes by finding "she" rather than "I" in the wrong places. But also keep in mind that the POV you choose may restrict what can be revealed to the reader through that particular lens. The tricky POV mistakes are the ones where the POV character acts based on something they couldn't possibly know or see. It may be as simple as a character not being present to "see" something happen but the action is described anyway.
But also consider the POV character's realm of knowledge. Would a janitor know the answers to combinatorial problems that even advanced mathematics students at MIT could not solve? Not likely. Unless of course that janitor was a genius in the story, as in the movie Good Will Hunting.
What POV do you like? Does it depend on the story?