I've been reading the Angry GM blog again, part out of remembering it and part out of needing another site to read. I don't always see eye to eye with the guy, but he has provided some things that made me think a bit.
This quote was in relation to how boredom can help a GM. Letting your mind wander and daydream, not taking in anything else, eyes open just zoned out. The post is about how to improve your narration through visualization practice (link here)
It's been interesting. A good way for me to spend my time as I lay in bed trying to go to sleep. Just trying to build a small space and just work on it bit by bit, sense by sense. Hoping this bit of practice here and there can eventually pay off.
Edit: I guess the main thrust of the post is that your imagination is a skill like any other, and a lot of people have let theirs atrophy because we just take stuff in with no real time to process or like... Work on things?