You're not surprised by the things that you expect when you return home after a long time. For example, walking into my house, and putting my backpack and guitar down seemed perfectly normal - I've done that hundreds of times after school.
But the doorknobs...the doorknobs threw me off. At Penn the doorknobs are all either handles or large globe-like constructions. The doorknobs at home are round, small, and flat. Also, my dogs smell (expectedly) faintly of dog, although I think that after less than 24 hours, I'm already used to the smell again.
It's the small things that get you - when you're not thinking about something and then it's different. I realized this when I reached into our cabinet for a bowl, and the big bowl and the small bowls and the plates were all exactly how I'd left them - but how easy would it have been for them to be different? I would have been completely derailed. Like when I reached into the kitchen drawer for a slip of paper from the pad that was usually there, but was now expended, the cardboard backing long since disposed of.
But still, when I look around and see the remnants of the paper on the kitchen table, the pages folded open to the crossword and sudoku puzzles, and a few scattered squeaky toys on the floor for my dogs, and the pot with the dregs of the tea from this morning idling in the kitchen, I realized that, thankfully, some things never change.