Your comment "You've come to expect the distance to be more out of focus because that is how you see it naturally" reminds me of when I was at school and I drew a picture that was all fuzzy and out of focus. The teacher critisied me for it and I couldnt understand why. Shortly afterwards I discovered that I was shortsighted and need glasses - suddenly everything came into focus and I realised what the teacher was on about...
Anyway, last night the images were very much further away (stars and rainbows) and very clear - so I guess you are right - whatever the images are, are approriate at the time - and they do change with practise.
