“All that is gold does not glitter, Not all those who wander all lost..." -JRR Tolkien
… And to see the difference requires perspective. The ability to understand your perspective. The ability to see others’ perspectives.
This ability is key in crafting stories. Everyone in a story has a unique view of the world. The protagonist sees things one way. A minor character sees it another. The antagonist sees himself not as the villain but as the hero. (And, if he doesn’t, you may want to reconsider your antagonist.)
An example of perspective is this picture below:
Obviously, it’s a picture of camels. But it’s not a picture of camels from a side. It’s from above as the sun sets. The camels themselves are hard to see–just their sandy backs are visible. The camels you clearly see are only their shadows. At first, you don’t see the camels themselves because of the perspective of the camera.
Everyone has a different perspective. Their cameras are in different places as they look at a situation.
As you write, always keep in mind others’ points of view. It’s perhaps one of the easiest ways to add depth and keep your characters behaving authentically and realistically. You know how your protagonist feels about everything–after all, that’s who the story centers around–but what would the story look like if told by the protagonists’ sidekick? Or by that minor character who dies in the twelfth chapter? Or by the antagonist?