I recently bought a house that had been previously occupied by smokers. During renovation I had something happen that I’ve never seen before or even heard of. I tried repainting one of the walls without any prep and it seemed like the paint went on fine even a couple of hours later, but when I came back the next morning the paint had all flowed down off the walls onto the floor. As best I can tell, the nicotine and tar on the walls penetrated the partially-dried paint like a solvent and re-liquified it. Fortunately, just wiping the walls down with mineral spirits before painting fixed the problem.