The previous owners of your home

What did the previous owners of your home hide from you during your inspection that you only noticed when you moved in?

The back of the house floods with a big rain. They built a sidewalk higher than the foundation, and it would become a swimming pool, and the water would seep into the house. I put in French drains and removed the sidewalk. I put in a more organic walk path and no more problem.

The previous owners hid the fact that the outside faucet leaked and caused seepage into the basement. They legally should not have hidden that and we probably could have sued. Once we got the plumbing job completed, we've never had seepage again.