I bought my house recently from a guy who had been renting it out for the last 40 years. He painted everything before putting it on the market but I didn't like the color. When I started the prep work for repainting, everything he put up peeled off like shelf paper. I was denouncing him as a total moron until the paint I put up did the same thing. In one room I even painted the walls and when I came back the next morning the paint had all flowed down to the floor and ruined the carpet.

Turns out the last tenant was a smoker and the walls were coated with nicotine. Had to wipe the whole house down with mineral spirits to get paint to stick.