DH and I live in a house built in 1860. Several generations of the same family lived it it. We bought it from the great-great grandson of the original builders, who grew up in the house.
We passed papers on June 30 and the seller was supposed to be out of the house on July 1. He overstayed an extra six days. It was legally our house at this point and we could have charged him rent but didn't.
When he left, he dismantled built-in shelves that he was supposed to leave for us. He promised to leave his fridge. He didn't - he took it with him and we had to buy one, an un-budgetted big expense. The dishwasher was broken, a fact he didn't disclose before the sale, so we had to buy one of those, too. He dug up plants from the garden and took them to his new house.
While moving out, he badly scratched the wooden floors in the living room. We had to have them refinished, another expense. He left the house filthy.
And best of all, three months after the sale, the former owner comes back to DH and me and says, "I just talked to someone who would have paid me $30,000 more for the house than you did. If I'd waited to sell to him, I'd have had that money. I think we should renegotiate the price you paid." We laughed at him. He threatened to sue us. We said go ahead and good luck to you.
Three years after moving in, DH and I built an addition to the house. We also painted it a new color. The new section was architecturally true to 1860 and blended in very nicely. We used a builder who specializes in period restorations. The house used to be a depressing battleship gray, now it's a light cheerful yellow. We get a call from the crazy former owner criticizing the "modern cracker box that we had tacked onto his beloved boyhood home" as well as the "the stupid color."
So jump forward a couple years, and the guy phones us and says that his grandchildren are visiting our town and he wants to bring them into our house "to tour their ancestral home."
I hadn't discovered this board in those days and hadn't yet learned the EHellion splendid phrase, "I'm afraid that won't be possible." I think what I said was, "What? Are you nuts? Don't come anywhere near this house!" and hung up on him.