Those non-things are either left out of the script or episodes are not made about them.
I liked that episode.
That's not my point. My point is that these are things which any normal person would dismiss as absurd or as a figment of imagination. But in Trek, they take every little thing seriously enough to have Geordi or Data or Wes run a scan on it.
"Did you guys see a shadow out of the corner or your eye?"
"Hmmm...my tricorder's not picking anything up beyond passive background theta rays."
"Captain, I think I felt something on the ground..."
"Sensors are detecting a large amount of rocks and detritus."
"Do you smell that...?"
"Reconfigure the main deflector to detect bio-trianic radiation!"
I mean, it's always, let's immediately assume this normal sounding shit is actually something we'd never detect unless we specifically focused this special device Wesley crapped out to detect plot holes!
I understand it's the future, and they're all enlightened and shit. But it strains credulity even more than crazy shit like shooting phasers at warp velocities. I mean, we been getting by for centuries thinking a bump in the night is nothing more dangerous than two people perhaps having midnight...bump.
But in the 24th century, they put entire work shifts on the problem.
It's like the writers can't find out a way to clue the characters into the problem without someone tripping over a duotronic alignment module that was dropped into the script. obviously it's not all the time, but it happened enough that it caught my attention.