Every waiter knows the secret pleasure of a waiter: hearing something that is not meant for you and taking action on it. Once on a hot day I heard a guest on 3 meters distant saying to a friend "Oh, I would die for a glass of water'". Several seconds later I stood there with it. The water had cost € 1,50 but her face expression was priceless! (and of course you pretend not to see that reaction;))
Four Seasons, a hotel chain with luxury hotels (in Paris they have the fabulous George V) is also listening to her guests even while they're not really talking to them. On Twitter! A guy complained that the music in his room was very dull. I'm sure his face would be priceless when he came back to his room where the housekeeping left a bottle of wine and a kind letter with a list of all the radiostations attached.
Keep the secret pleasure alive! (and enjoy it....)