This is one of those details that can take a good story and make it great.
We’ll start with definitions, as we usually do:
Filter Words: extra phrases meant to establish a character’s perception. They filter the story through the main character’s senses.
Example: He saw, she felt, he remembered, they heard, etc.
There’s nothing inherently wrong with any of these phrases–sometimes you need them–but these extra words put extra distance between the reader and the story, and sometimes that can keep the reader from getting properly engaged with what’s going on.
He saw the gates open up, and he felt cold air blast his face. He heard the wind howl, and he remembered how beautiful this place had looked back before the Frozen King seized the throne. Now it was nothing but ruin.
The gates opened wide, and cold air blasted his face. The wind howled. This place had been so beautiful before the Frozen King seized the throne. Now, it was nothing but ruin.
The first example isn’t necessarily bad, but the second one is a lot more intimate. And though they’re both fine on the scale of a paragraph, that first option can get grating if you let it carry throughout a whole story
As a reader, I know the character is seeing and hearing and feeling these things. You wouldn’t be mentioning them if they weren’t. And that constant reminder that the character perceives stuff is the literary equivalent of those vacation photos where you can’t see the sights cause the photographer’s thumb is in the way.
It takes the reader and it pushes them out of the story. It forces a sort of distance you might not want to keep.
Let the reader see the world through the character’s eyes without making them feel like they’re riding around in a character-shaped meat-suit. Try taking out those filler words when you see them and see what happens.
It’s a relatively small tweak, but it makes enough of a difference that it’s worth keeping in mind.