When they were near the top floor, the first friend remarked that he will them a story with the most horrifying ending possible: "I forgot the room keys in the car!"
Obviously they had no choice but to go all the way down, just when they were about to reach the car, the second friend remarked: "I have an even more horrifying story ... I have the keys in my pocket."
So well they again started climbing, very near the top the third friend remarked this time: "Ha!, I can beat you both, I have the most horrifying story possible ... We are in the wrong building, ours is the adjacent one!"