Even things that are seemingly “throw away” scenes come back. Sirius’ flying motorbike is the most obvious. Fred and George play the, “I’m not Fred! He is!” gag on Moody that they played on Molly at King’s Cross in SS.
Maybe because I was reading very quickly, and late into the night, but I fell for every one of her tricks in the POA. I felt true terror when Sirius Black was in the castle, and somehow "mistook" Ron's bed for Harry's. The events in the Shrieking Shack later in the book were mind-boggling to me. No longer could the most insignificant of mentions of anything be treated lightly.
I remain in awe of the complexity of this tale. Those who scoff at it don't know of what they speak.