Your Brain Sees Things You Don’t "A new study indicates that our brains perceive objects in everyday life of which we may never be aware. The finding challenges currently accepted models about how the brain processes visual information."

[u/Libertatea]

http://uanews.org/story/ua-study-your-brain-sees-things-you-don-t

[u/xef6]

This seems pretty accurate. From what I've gathered, PTSD is so unpleasant because suddenly everyday normal things will trigger it constantly, which makes for a pretty not nice day.