I have one:
When I first moved out on my own, my mother took me to see a friend of hers that ran a rental agency. I wanted to be in El Cerrito, closer to my job. However, Friend took us to two apartments in Richmond: a tenement on 3rd Street that had used needles all over the lawn and stairs, and an sub-let in Atchinson Village that someone had lived (and smoked heavily) in for years. My mother was so insulted and told the friend on the spot to take us back to the office and never contact her again.
When I was looking for our first house, our realtor took us to a house in our price range that had a pool. Before walking into the place, I was thinking Hey! It has a pool! Once inside, it turned out that the pool covered the entire backyard space, so you literally stepped out the back door and found yourself in the pool. Their living area was swallowed up by a huge sectional and a T.V. The rest of the house was not dirty, but messy and bare bones (no bedroom furniture, clothes stacked on the floor). But the deal breaker was the kitchen - burnt orange everything (island, appliances, cupboards). My realtor was very angry and tight-lipped as we left. She said, "I know exactly what happened there" and nothing more.