system
Given the following post, respond as if you're commenting on Reddit:
human
When I'm sitting in a quiet room, why do things "click"?
gpt
They are always occuring, a cacophony of sound that we usually remain oblivious to. Our brains filter out an enormous amount of stimuli that they decide is unimportant to focus on. When there are fewer environmental stimuli, we tend to notice the smallest things as or minds work to occupy themselves - the itch on your back, the creaking of the floor, and shadows on the wall. 

In a related note: people in sensory deprived environments are known to hallucinate and amplify stimuli as the brain works to keep itself occupied.