In most cases, moving into a new house means you're entering a completely blank space: the rooms are cleared and freshly painted, ready for you to fill them with all of your decorations and emotions.
While there are few feelings more cathartic than entering a fresh space ready for you to nest, not all move-ins are this smooth. When you buy an old house there are often old treasures (or terrors) waiting to be discovered in the attics and basement floorboards, and these can often make for a rabbit-hole of curiosity.
When I was a kid we moved into a house that had been built in the 1920's. Mom found a barrel in the crawl space full of crystal glasses from before the depression and lots of other very nice dishes. Mom was stoked.
We moved into an old house where the same family had lived from about 1945 to 1998. I was cleaning the attic and happened to move some of the blown-in insulation. I saw what looked like a book. I dug around and found several things. The 1969 Sears Roebuck catalog was intact, so I set that aside and kept digging because there was more. The most interesting item was a girl's diary which she had kept from around 1952 to 1957, her teenage years. I read the whole thing, and it made me sad in a way because here was this young girl writing about her life and now she must be in her 60s and these old memories have been locked away here all this time.