Sometimes everything looks more "real" than other times. I can't explain it further than that; possibly there's a connection with my level of attentiveness. It's even more pronounced when I'm in a lucid dream and my mind is actually manufacturing the sensory information: When I pay attention to something, it becomes more detailed, bright, and sharply focused. Possibly this is a carryover from my brain's waking operation, when my brain processes only the sensory information it's focused on?
But I don't think this has anything to do with parallel dimensions; remember that our image of our surroundings is manufactured entirely in the brain and has no direct connections with the actual stimuli. Therefore, if your brain connects your mood with your surroundings, you will perceive some of that mood as sensory information.
Perhaps this is a sort of synesthesia? If so, it can't be rare--I see in descriptions of characters' thoughts in books that the author often has them perceiving their surroundings according to their moods; and if NT authors experience it, surely many others do as well? Also, there is the idiom "seeing red", which means that a person is angry.